Journal tags: progressive

I’ve been deep-diving into HTML web components over the past few weeks. I decided to refactor the JavaScript on The Session to use custom elements wherever it made sense.

I really enjoyed doing this, even though the end result for users is exactly the same as before. This was one of those refactors that was for me, and also for future me. The front-end codebase looks a lot more understandable and therefore maintainable.

Most of the JavaScript on The Session is good ol’ DOM scripting. Listen for events; when an event happens, make some update to some element. It’s the kind of stuff we might have used jQuery for in the past.

Chris invoked Betteridge’s law of headlines recently by asking Will Web Components replace React and Vue? I agree with his assessment. The reactivity you get with full-on frameworks isn’t something that web components offer. But I do think web components can replace jQuery and other approaches to scripting the DOM.

I’ve written about my preferred way to do DOM scripting: element.target.closest. One of the advantages to that approach is that even if the DOM gets updated—perhaps via Ajax—the event listening will still work.

Well, this is exactly the kind of thing that custom elements take care of for you. The connectedCallback method gets fired whenever an instance of the custom element is added to the document, regardless of whether that’s in the initial page load or later in an Ajax update.

So my client-side scripting style has updated over time:

1. Adding event handlers directly to elements.
2. Adding event handlers to the document and using event.target.closest.
3. Wrapping elements in a web component that handles the event listening.

None of these progressions were particularly ground-breaking or allowed me to do anything I couldn’t do previously. But each progression improved the resilience and maintainability of my code.

Like Chris, I’m using web components to progressively enhance what’s already in the markup. In fact, looking at the code that Chris is sharing, I think we may be writing some very similar web components!

A few patterns have emerged for me…

Naming custom elements

Naming things is famously hard. Every time you make a new custom element you have to give it a name that includes a hyphen. I settled on the convention of using the first part of the name to echo the element being enhanced.

If I’m adding an enhancement to a button element, I’ll wrap it in a custom element that starts with button-. I’ve now got custom elements like button-geolocate, button-confirm, button-clipboard and so on.

Likewise if the custom element is enhancing a link, it will begin with a-. If it’s enhancing a form, it will begin with form-.

The name of the custom element tells me how it’s expected to be used. If I find myself wrapping a div with button-geolocate I shouldn’t be surprised when it doesn’t work.

Naming attributes

You can use any attributes you want on a web component. You made up the name of the custom element and you can make up the names of the attributes too.

I’m a little nervous about this. What if HTML ends up with a new global attribute in the future that clashes with something I’ve invented? It’s unlikely but it still makes me wary.

So I use data- attributes. I’ve already got a hyphen in the name of my custom element, so it makes sense to have hyphens in my attributes too. And by using data- attributes, the browser gives me automatic reflection of the value in the dataset property.

Instead of getting a value with this.getAttribute('maximum') I get to use this.dataset.maximum. Nice and neat.

The single responsibility principle

My favourite web components aren’t all-singing, all-dancing powerhouses. Rather they do one thing, often a very simple thing.

Here are some examples:

• Jason’s aria-collapsable for toggling the display of one element when you click on another.
• David’s play-button for adding a play button to an audio or video element.
• Chris’s ajax-form for sending a form via Ajax instead of a full page refresh.
• Jim’s user-avatar for adding a tooltip to an image.
• Zach’s table-saw for making tables responsive.

All of those are HTML web components in that they extend your existing markup rather than JavaScript web components that are used to replace HTML. All of those are also unambitious by design. They each do one thing and one thing only.

But what if my web component needs to do two things?

I make two web components.

The beauty of custom elements is that they can be used just like regular HTML elements. And the beauty of HTML is that it’s composable.

What if you’ve got some text that you want to be a level-three heading and also a link? You don’t bemoan the lack of an element that does both things. You wrap an a element in an h3 element.

The same goes for custom elements. If I find myself adding multiple behaviours to a single custom element, I stop and ask myself if this should be multiple custom elements instead.

Take some of those button- elements I mentioned earlier. One of them copies text to the clipboard, button-clipboard. Another throws up a confirmation dialog to complete an action, button-confirm. Suppose I want users to confirm when they’re copying something to their clipboard (not a realistic example, I admit). I don’t have to create a new hybrid web component. Instead I wrap the button in the two existing custom elements.

Rather than having a few powerful web components, I like having lots of simple web components. The power comes with how they’re combined. Like Unix pipes. And it has the added benefit of stopping my code getting too complex and hard to understand.

Communicating across components

Okay, so I’ve broken all of my behavioural enhancements down into single-responsibility web components. But what if one web component needs to have awareness of something that happens in another web component?

Here’s an example from The Session: the results page when you search for sessions in London.

There’s a map. That’s one web component. There’s a list of locations. That’s another web component. There are links for traversing backwards and forwards through the locations via Ajax. Those links are in web components too.

I want the map to update when the list of locations changes. Where should that logic live? How do I get the list of locations to communicate with the map?

Events!

When a list of locations is added to the document, it emits a custom event that bubbles all the way up. In fact, that’s all this component does.

You can call the event anything you want. It could be a newLocations event. That event is dispatched in the connectedCallback of the component.

Meanwhile in the map component, an event listener listens for any newLocations events on the document. When that event handler is triggered, the map updates.

The web component that lists locations has no idea that there’s a map on the same page. It doesn’t need to. It just needs to dispatch its event, no questions asked.

There’s nothing specific to web components here. Event-driven programming is a tried and tested approach. It’s just a little easier to do thanks to the connectedCallback method.

I’m documenting all this here as a snapshot of my current thinking on HTML web components when it comes to:

• naming custom elements,
• naming attributes,
• the single responsibility principle, and
• communicating across components.

I may well end up changing my approach again in the future. For now though, these ideas are serving me well.

Those HTML web components I made for date inputs are very simple. All they do is slightly extend the behaviour of the existing input elements.

This would be the ideal use-case for the is attribute:

<input is="input-date-future" type="date">

Alas, Apple have gone on record to say that they will never ship support for customized built-in elements.

So instead we have to make HTML web components by wrapping existing elements in new custom elements:

<input-date-future>
  <input type="date">
<input-date-future>

The end result is the same. Mostly.

Because there’s now an additional element in the DOM, there could be unexpected styling implications. Like, suppose the original element was direct child of a flex or grid container. Now that will no longer be true.

So something I’ve started doing with HTML web components like these is adding something like this inside the connectedCallback method:

connectedCallback() {
    this.style.display = 'contents';
  …
}

This tells the browser that, as far as styling is concerned, there’s nothing to see here. Move along.

Or you could (and probably should) do it in your stylesheet instead:

input-date-future {
  display: contents;
}

Just to be clear, you should only use display: contents if your HTML web component is augmenting what’s within it. If you add any behaviours or styling to the custom element itself, then don’t add this style declaration.

It’s a bit of a hack to work around the lack of universal support for the is attribute, but it’ll do.

I had the opportunity to trim some code from The Session recently. That’s always a good feeling.

In this case, it was a progressive enhancement pattern that was no longer needed. Kind of like removing a polyfill.

There are a couple of places on the site where you can input a date. This is exactly what input type="date" is for. But when I was making the interface, the support for this type of input was patchy.

So instead the interface used three select dropdowns: one for days, one for months, and one for years. Then I did a bit of feature detection and if the browser supported input type="date", I replaced the three selects with one date input.

It was a little fiddly but it worked.

Fast forward to today and input type="date" is supported across the board. So I threw away the JavaScript and updated the HTML to use date inputs by default. Nice!

I was discussing date inputs recently when I was talking to students in Amsterdam:

They’re given a PDF inheritance-tax form and told to convert it for the web.

That form included dates. The dates were all in the past so the students wanted to be able to set a max value on the datepicker. Ideally that should be done on the server, but it would be nice if you could easily do it in the browser too.

Wouldn’t it be nice if you could specify past dates like this?

<input type="date" max="today">

Or for future dates:

<input type="date" min="today">

Alas, no such syntactic sugar exists in HTML so we need to use JavaScript.

This seems like an ideal use-case for HTML web components:

Instead of all-singing, all-dancing web components, it feels a lot more elegant to use web components to augment your existing markup with just enough extra behaviour.

In this case, it would be nice to augment an existing input type="date" element. Something like this:

 <input-date-past>
   <input type="date">
 </input-date-past>

Here’s the JavaScript that does the augmentation:

 customElements.define('input-date-past', class extends HTMLElement {
     constructor() {
         super();
     }
     connectedCallback() {
         this.querySelector('input[type="date"]').setAttribute('max', new Date().toISOString().substring(0,10));
     }
 });

That’s it.

Here’s a CodePen where you can see it in action along with another HTML web component for future dates called, you guessed it, input-date-future.

See the Pen Date input HTML web components by Jeremy Keith (@adactio) on CodePen.

There’s a lovely CSS property called hanging-punctuation. You can use it to do exactly what the name suggests and exdent punctuation marks such as opening quotes.

Here’s one way to apply it:

html {
  hanging-punctuation: first last;
}

Any punctuation marks at the beginning or end of a line will now hang over the edge, leaving you with nice clean blocks of text; no ragged edges.

Right now it’s only supported in Safari but there’s no reason not to use it. It’s a perfect example of progressive enhancement. One line of CSS to tidy things up for the browsers that support it and leave things exactly as they are for the browsers that don’t.

But when I used this over on The Session I noticed an unintended side-effect. Because I’m applying the property globally, it’s also acting on form fields. If the text inside a form field starts with a quotation mark or some other piece of punctuation, it’s shunted off to the side and hidden.

Here’s the fix I used:

input, textarea {
  hanging-punctuation: none;
}

It’s a small little gotcha but I figured I’d share it in case it helps someone else out.

When I wrote about my time in Amsterdam last week, I mentioned the task that the students were given:

They’re given a PDF inheritance-tax form and told to convert it for the web.

Rich had a question about that:

I’m curious to know if they had the opportunity to optimise the user experience of the form for an online environment, eg. splitting it up into a sequence of questions, using progressive disclosure, branching based on inputs, etc?

The answer is yes, very much so. Progressive disclosure was a very clear opportunity for enhancement.

You know the kind of paper form where it says “If you answered no to this, then skip ahead to that”? On the web, we can do the skipping automatically. Or to put it another way, we can display a section of the form only when the user has ticked the appropriate box.

This is a classic example of progressive disclosure:

information is revealed when it becomes relevant to the current task.

But what should the mechanism be?

This is an interaction design pattern so JavaScript seems the best choice. JavaScript is for behaviour.

On the other hand, you can do this in CSS using the :checked pseudo-class. And the principle of least power suggests using the least powerful language suitable for a given task.

I’m torn on this. I’m not sure if there’s a correct answer. I’d probably lean towards JavaScript just because it’s then possible to dynamically update ARIA attributes like aria-expanded—very handy in combination with aria-controls. But using CSS also seems perfectly reasonable to me.

It was interesting to see which students went down the JavaScript route and which ones used CSS.

It used to be that using the :checked pseudo-class involved an adjacent sibling selector, like this:

input.disclosure-switch:checked ~ .disclosure-content {
  display: block;
}

That meant your markup had to follow a specific pattern where the elements needed to be siblings:

<div class="disclosure-container">
  <input type="checkbox" class="disclosure-switch">
  <div class="disclosure-content">
  ...
  </div>
</div>

But none of the students were doing that. They were all using :has(). That meant that their selector could be much more robust. Even if the nesting of their markup changes, the CSS will still work. Something like this:

.disclosure-container:has(.disclosure-switch:checked) .disclosure-content

That will target the .disclosure-content element anywhere inside the same .disclosure-container that has the .disclosure-switch. Much better! (Ignore these class names by the way—I’m just making them up to illustrate the idea.)

But just about every student ended up with something like this in their style sheets:

.disclosure-content {
  display: none;
}
.disclosure-container:has(.disclosure-switch:checked) .disclosure-content {
  display: block;
}

That gets my spidey-senses tingling. It doesn’t smell right to me. Here’s why…

The simpler selector is doing the more destructive action: hiding content. There’s a reliance on the more complex selector to display content.

If a browser understands the first ruleset but not the second, that content will be hidden by default.

I know that :has() is very well supported now, but this still makes me nervous. I feel that the more risky action (hiding content) should belong to the more complex selector.

Thanks to the :not() selector, you can reverse the logic of the progressive disclosure:

.disclosure-content {
  display: block;
}
.disclosure-container:not(:has(.disclosure-switch:checked)) .disclosure-content {
  display: none;
}

Now if a browser understands the first ruleset, but not the second, it’s not so bad. The content remains visible.

When I was explaining this way of thinking to the students, I used an analogy.

Suppose you’re building a physical product that uses electricity. What should happen if there’s a power cut? Like, if you’ve got a building with electric doors, what should happen when the power is cut off? Should the doors be locked by default? Or is it safer to default to unlocked doors?

It’s a bit of a tortured analogy, but it’s one I’ve used in the past when talking about JavaScript on the web. I like to think about JavaScript as being like electricity…

Take an existing product, like say, a toothbrush. Now imagine what you can do when you turbo-charge it with electricity: an electric toothbrush!

But also consider what happens when the electricity fails. Instead of the product becoming useless you want it to revert back to being a regular old toothbrush.

That’s the same mindset I’m encouraging for the progressive disclosure pattern. Make sure that the default state is safe. Then enhance.

I was in Amsterdam last week. Usually I’m in that city for an event like the excellent CSS Day. Not this time. I was there as a guest of Vasilis. He invited me over to bother his students at the CMD (Communications and Multimedia Design) school.

There’s a specific module his students are partaking in that’s right up my alley. They’re given a PDF inheritance-tax form and told to convert it for the web.

Yes, all the excitement of taxes combined with the thrilling world of web forms.

Seriously though, I genuinely get excited by the potential for progressive enhancement here. Sure, there’s the obvious approach of building in layers; HTML first, then CSS, then a sprinkling of JavaScript. But there’s also so much potential for enhancement within each layer.

Got your form fields marked up with the right input types? Great! Now what about autocomplete, inputmode, or pattern attributes?

Got your styles all looking good on the screen? Great! Now what about print styles?

Got form validation working? Great! Now how might you use local storage to save data locally?

As well as taking this practical module, most of the students were also taking a different module looking at creative uses of CSS, like making digital fireworks, or creating works of art with a single div. It was fascinating to see how the different students responded to the different tasks. Some people loved the creative coding and dreaded the progressive enhancement. For others it was exactly the opposite.

Having to switch gears between modules reminded me of switching between prototypes and production:

Alternating between production projects and prototyping projects can be quite fun, if a little disorienting. It’s almost like I have to flip a switch in my brain to change tracks.

Here’s something I noticed: the students love using :has() in CSS. That’s so great to see! Whereas I might think about how to do something for a few minutes before I think of reaching for :has(), they’ve got front of mind. I’m jealous!

In general, their challenges weren’t with the vocabulary or syntax of HTML, CSS, and JavaScript. The more universal problem was project management. Where to start? What order to do things in? How long to spend on different tasks?

If you can get good at dealing with those questions and not getting overwhelmed, then the specifics of the actual coding will be easier to handle.

This was particularly apparent when it came to JavaScript, the layer of the web stack that was scariest for many of the students.

I encouraged them to break their JavaScript enhancements into two tasks: what you want to do, and how you then execute that.

Start by writing out the logic of your script not in JavaScript, but in whatever language you’re most comfortable with: English, Dutch, whatever. In the course of writing this down, you’ll discover and solve some logical issues. You can also run your plain-language plan past a peer to sense-check it.

It’s only then that you move on to translating your logic into JavaScript. Under each line of English or Dutch, write the corresponding JavaScript. You might as well put // in front of the plain-language sentence while you’re at it to make it a comment—now you’ve got documentation baked in.

You’ll still run into problems at this point, but they’ll be the manageable problems of syntax and typos.

So in the end, it wasn’t my knowledge of specific HTML, CSS, or JavaScript APIs that proved most useful to pass on to the students. It was advice like that around how to approach HTML, CSS, or JavaScript.

I also learned a lot during my time at the school. I had some very inspiring conversations with the web developers of tomorrow. And I was really impressed by how much the students got done just in the three days I was hanging around.

I’d love to do it again sometime.

The European Union’s Digital Markets Act is being enforced and Apple aren’t happy about it.

Most of the discussion around this topic has centred on the requirement for Apple to provision alternative app stores. I don’t really care about that because I don’t really care about native apps. With one exception: I care about web browsers.

That’s the other part of the DMA that’s being enforced: Apple finally have to allow alternative browsing engines. Hallelujah!

Instead of graciously acknowledging that this is what’s best for users, Apple are throwing a tantrum.

First of all, they’re going to ringfence any compliance to users in the European Union. Expect some very interesting edge cases to emerge in a world where people don’t spent their entire lives in one country.

Secondly, Apple keep insisting that this will be very, very bad for security. You can read Apple’s announcement on being forced to comply but as you do you so, I’d like you to remember one thing: every nightmare scenario they describe for the security of users in the EU is exactly what currently happens on Macs everywhere in the world.

This includes risks from installing software from unknown developers that are not subject to the Apple Developer Program requirements, installing software that compromises system integrity with malware or other malicious code, the distribution of pirated software, exposure to illicit, objectionable, and harmful content due to lower content and moderation standards, and increased risks of scams, fraud, and abuse.

Users of macOS everywhere are currently exposed to all the risks that will supposedly overwhelm iOS users in the European Union. Weirdly, the sky hasn’t fallen.

It’s the same with web browsers. I just got a new Mac. It came with one browser pre-installed: Safari. It’s a good browser. But I also have the option of installing another browser, like Firefox (which I’ve done). A lot of people just use Safari. That’s good. That’s choice. Everyone wins.

Now Apple need to provide parity on iOS, at least for users in the EU. Again, Apple are decribing this coming scenario as an absolute security nightmare. But again, the conditions they’re describing are what already exist on macOS.

All Apple is being asked to do is offer than the same level of choice on mobile that everyone already enjoys on their computers. Rather than comply reasonably, Apple have found a way to throw their toys out of the pram.

As of the next update to iOS, users in the EU will no longer have homescreen apps. Those web apps will now launch in a browser window. Presumably they’ll also lose the ability to send push notifications: being a homescreen app was a prerequisite for that functionality.

This is a huge regression that only serves to harm and confuse users.

I have a website about traditional Irish music. Guess where a significant amount of the audience is based? That’s right: Ireland. In the European Union.

There is no native app for The Session, but you can install it on your phone nonetheless. Lots of people have done that. After a while they forget that they didn’t install it from an app store: it behaves just like any other app on their homescreen.

That’s all about to change. I’m going to get a lot of emails from confused users wondering why their app is broken, now opening in a regular browser window. And I won’t be able to do anything about it, other than to tell them to take it up with Apple.

Presumably Apple is hoping that users will direct their anger at the EU commission instead. They’re doing their best to claim that they’re being forced to make this change. That’s completely untrue. A lie:

This is emphatically not required by the EU’s Digital Markets Act (DMA). It’s a circumvention of both the spirit and the letter of the Act, and if the EU allows it, then the DMA will have failed in its aim to allow fair and effective browser and web app competition.

Throughout all their communications on this topic, Apple are sticking to their abuser logic:

Look what you made me do!

This is going to hurt me more than it hurts you.

Apple’s petulant policy of malicious compliance is extremely maddening. What they’re about to do to users in the EU is just nasty.

This is a very dark time for the web.

I feel bad for the Safari team. They’ve been working really hard recently to make Safari a very competitive browser with great standards support with a quicker release cycle than we’ve seen before. Then it all gets completely torpedoed at the level of the operating system.

I really hope that Apple won’t get away with their plan to burn down web apps on iOS in the EU. But hope isn’t enough. We need to tell the EU commission how much damage this will do.

If you’ve ever built a web app, then your users will suffer. Remember, it’s a world wide web, including the European Union.

Create a PDF with the following information:

• Your company’s name.
• Your name.
• That your company operates or services the EU.
• How many users your service has in the EU (approximately).
• The level of impact this will have on your business.
• The problems this will cause your business.
• Whether or not the submission is confidential.

The submission can be as short or long as you want. Send it to contactus@open-web-advocacy.org, ideally before Monday, February 19th.

I know that’s a lot to ask of you on your weekend, but this really matters for the future of the web.

At the very least, I encourage to get involved with the great work being done by the Open Web Advocacy group. They’re also on Discord.

Please don’t let Apple bully an entire continent of users.

I was impressed with how Safari now allows you to add websites to the dock:

It feels great to have websites that act just like other apps. I like that some of the icons in my dock are native, some are web apps, and I mostly don’t notice the difference.

Trys liked it too:

For all intents and purposes, this is a desktop application created without a single line of Swift or Objective-C, or any heavy Electron wrappers.

Oh, and the application can work offline! Service workers, and browser storage are more than stable enough to handle a variety of offline loading patterns. These are truly exciting times to be building for the web!

There was one aspect that I was particularly pleased with. External links:

Links within a Safari-installed web app respect your default browser choice.

Excellent! Except it’s no longer true. At least not in some cases. The behaviour is inconsisent but I’m running the latest version of Safari on the latest version of Sonoma, and now external links in a Safari-installed web app are broken. They just stay in the same application.

I thought maybe it was related to whether the website’s manifest file has the display value set to “standalone” rather than, say, “minimal ui”. Maybe the “standalone” instruction is being taken literally? But even when I change the value I’m still getting the broken behaviour.

This may sound like a small thing, but it completely changes the feel of using the web app. Instead of feeling like “I’m using an app that just happens to be on the web”, it now feels like “I’m using a web browser but with fewer features.”

I’ve been loving having Mastodon as a standalone app in my dock. It used to be that if I clicked on a link in a Mastodon post, it would open in my browser of choice (Firefox) where I could then bookmark it, or do any other tasks that my browser offers me. Now if I click on a link in Mastodon, I’m stuck in the same “app”. It feels horribly stifling.

I can right-click on a link and get options that still keep me in the same app, like “Open link” or “Open Link in New Window.” To actually open the link in my web browser, I have to select “Copy Link”, then go to my web browser, open a new tab, and paste the link in there.

This is broken. I hope it isn’t intentional. Maybe I’m just at the receiving end of some weird glitch. If this stays this way, I’ll probably just remove the Safari-installed web apps from my dock. They feel pointless if they’re just roach motels.

I’d love to file a bug for this, but this isn’t a Webkit bug, it’s a Safari bug (and the Webkit bug tracker is at pains to point out that Webkit and Safari are not the same thing). But have you ever tried to file a bug with Apple? Good luck!

Anyway, I sincerely hope that this change will be walked back. Otherwise websites in the dock are dead in the water.

Web components have been around for quite a while, but it feels like they’re having a bit of a moment right now.

It turns out that the best selling point for web components was “wait and see.” For everyone who didn’t see the benefit of web components over being locked into a specific framework, time is proving to be a great teacher.

It’s not just that web components are portable. They’re also web standards, which means they’ll be around as long as web browsers. No framework can make that claim. As Jake Lazaroff puts it, web components will outlive your JavaScript framework.

At this point React is legacy technology, like Angular. Lots of people are still using it, but nobody can quite remember why. The decision-makers in organisations who chose to build everything with React have long since left. People starting new projects who still decide to build on React are doing it largely out of habit.

Others are making more sensible judgements and, having been bitten by lock-in in the past, are now giving web components a go.

If you’re one of those people making the move from React to web components, there’ll certainly be a bit of a learning curve, but that would be true of any technology change.

I have a suggestion for you if you find yourself in this position. Try not to bring React’s mindset with you.

I’m talking about the way React components are composed. There’s often lots of props doing heavy lifting. The actual component element itself might be empty.

If you want to apply that model to web components, you can. Lots of people do. It’s not unusual to see web components in the wild that look like this:

<my-component></my-component>

The custom element is just a shell. All the actual power is elsewhere. It’s in the JavaScript that does all kinds of clever things with the shadow DOM, templates, and slots.

There is another way. Ask, as Robin does, “what would HTML do?”

Think about composibility with existing materials. Do you really need to invent an entirely new component from scratch? Or can you use HTML up until it reaches its limit and then enhance the markup?

Robin writes:

I don’t think we should see web components like the ones you might find in a huge monolithic React app: your Button or Table or Input components. Instead, I’ve started to come around and see Web Components as filling in the blanks of what we can do with hypertext: they’re really just small, reusable chunks of code that extends the language of HTML.

Dave talks about how web components can be HTML with superpowers. I think that’s a good attitude to have. Instead of all-singing, all-dancing web components, it feels a lot more elegant to use web components to augment your existing markup with just enough extra behaviour.

Where does the shadow DOM come into all of this? It doesn’t. And that’s okay. I’m not saying it should be avoided completely, but it should be a last resort. See how far you can get with the composibility of regular HTML first.

Eric described his recent epiphany with web components. He created a super-slider custom element that wraps around an existing label and input type="range":

You just take some normal HTML markup, wrap it with a custom element, and then write some JS to add capabilities which you can then style with regular CSS!  Everything’s of the Light Side of the Web.  No need to pierce the Vale of Shadows or whatever.

When you wrap some existing markup in a custom element and then apply some new behaviour with JavaScript, technically you’re not doing anything you couldn’t have done before with some DOM traversal and event handling. But it’s less fragile to do it with a web component. It’s portable. It obeys the single responsibility principle. It only does one thing but it does it well.

Jim created an icon-list custom element that wraps around a regular ul populated with li elements. But he feels almost bashful about even calling it a web component:

Maybe I shouldn’t be using the term “web component” for what I’ve done here. I’m not using shadow DOM. I’m not using the templates or slots. I’m really only using custom elements to attach functionality to a specific kind of component.

I think what Eric and Jim are doing is exemplary. See also Zach’s web components.

At the end of his post, Eric says he’d like a nice catchy term for these kinds of web components. In Dave’s catalogue of web components, they’re called “element extensions.” I like that. It’s pretty catchy.

Or we could call them “HTML web components.” If your custom element is empty, it’s not an HTML web component. But if you’re using a custom element to extend existing markup, that’s an HTML web component.

React encouraged a mindset of replacement: “forgot what browsers can do; do everything in a React component instead, even if you’re reinventing the wheel.”

HTML web components encourage a mindset of augmentation instead.

I updated my Mac to the newest operating system, Sonoma. I did this to try out the new “add to Dock” feature in Safari. It’s like the “add to Homescreen” action on iOS.

Before I get into what’s good, I have to start by ranting about a big problem on both desktop and mobile: discovery.

First of all, you have to know that a square with an arrow sticking out of it means “share”.

Okay, I can buy it. It’s no better or worse than the three horizontal lines of a hamburger icon, or the three horizontal dots of a kebab icon. And whereas the hamburger and kebab icons are used as a catch-all cupboard to sweep all your rubbish into, at least this icon has a specific meaning. It means share, right?

Well, it used to. But now it’s also home to “add to Homescreen” and “add to Dock”. Neither of those actions are sharing.

Stretching semantics, I suppose you could say you’re sharing something with yourself.

Anyway, this is the biggest issue with progressive web apps on both iOS and Mac. Regardless of how well they work, there’s not much point if most people don’t know the option exists.

(Update: Jen rightly points out that you can also get to “add to Dock” from the file menu. Doh! How did I miss that‽)

Discovery aside, I was interested to see how Safari handles web apps on desktop compared to how Chrome does it.

I’ve had one or two web apps in my dock for a while, installed through Chrome. Google Meet is one of them. I use it quite a bit, and honestly it feels no different to using a native desktop app.

One annoyance is that the Chrome browser also automatically launches whenever I launch the Google Meet icon in my dock. This wouldn’t matter if Chrome were my default browser, but I use Firefox. So whenever I’m using the Google Meet web app, there’s a Google Chrome icon hanging around in my dock, saying “gizza job, I can do that.”

I opened Google Meet in Safari and then selected “add to Dock” from the square with an arrow sticking out of it. Then I quit Safari. I was delighted to see that when I launched the Google Meet web app from the dock, it didn’t automatically launch Safari! Excellent!

Even better, links within a Safari-installed web app respect your default browser choice. What I mean is, previously when I had Google Meet installed via Chrome, if I clicked an external link in Google Meet it opened in Chrome. But now with the Google Meet installed via Safari, external links open in Firefox, my browser of choice. Very good!

But the Safari-installed version of Google Meet is, alas, over-zealous with permissions. I have to grant access to my microphone and camera every single time I launch it. Previously—with the version installed via Chrome—it remembered my choice.

Now I don’t know if the behaviour in the Safari-installed version is a deliberate choice made for security reasons, or if it’s a bug. I suspect it’s a bug. After all, on iOS you get access to more permissions if a site is added to the homescreen—it’s the only way to ask for permissions for notifications, for example.

I added a few more sites to my dock: mastodon.social and thesession.org. They both work really well as standalone apps.

Interestingly, if I click a link to thesession.org from within the mastodon.social standalone web app (or the other way around), the link opens in my default browser. So the web apps don’t “own” the domains. That’s fine, although I wonder if it violates the principle of least surprise—perhaps the expectation is that the installed web app is the preffered owner of that link.

I also tried adding Google Calendar to my dock. Ironically, I can only do this with Safari. For some reason, Google have chosen not to make their calendar a progressive web app …which means there’s no option to install it from Google Chrome.

They’re missing a trick there. It’s the perfect candidate for being a standalone app.

Actually, I take that back. Gmail is the perfect candidate for being a standalone app …and yet it’s not a progressive web app. Very odd!

With Safari, you can add any website to the dock. It doesn’t need to be a progressive web app. But the installation experience works best if there’s a manifest file pointing to some nice icons.

As it turned out, Google Calendar runs like an absolute dog in Safari (and therefore as a Safari-installed web app). Before you cry conspiracy, note that it runs absolutely fine in Firefox. I know because I use it in Firefox every day. But I can’t add it to my dock from Firefox because Mozilla turned their back on progressive web apps a while back. A bad decision.

Google Calendar isn’t the only thing that runs slowly in Safari’s engine. This page on The Session has a very large DOM and a badly-coded in-page search (I know, I know, I need to improve it). It works fine in other browsers but Safari struggles mightily.

(Update: I tried using Google Calendar from Safari again and it seems to be running just fine now. Maybe I caught it on a bad day? In any case, I’ve added it to the dock now and it’s feeling good as a standalone app.)

Still, aside from a few annoying little things around permissions and performance—and the situation with discovery—it feels great to have websites that act just like other apps. I like that some of the icons in my dock are native, some are web apps, and I mostly don’t notice the difference.

I wonder if there’s much point using wrappers like Electron any more? I feel like they were mostly aiming to get that parity with native apps in having a standalone application launched from the dock.

Now all you need is a website.

I must admit, when Jake told me he was leaving Google, I got very worried about the future of the View Transitions API.

To recap: Chrome shipped support for the API, but only for single page apps. That had me worried:

If the View Transitions API works across page navigations, it could be the single best thing to happen to the web in years.

If the View Transitions API only works for single page apps, it could be the single worst thing to happen to the web in years.

Well, the multi-page version still hasn’t yet shipped in Chrome stable, but it is available in Chrome Canary behind a flag, so it looks like it’s almost here!

Robin took the words out of my mouth:

Anyway, even this cynical jerk is excited about this thing.

Are you the kind of person who flips feature flags on in nightly builds to test new APIs?

Me neither.

But I made an exception for the View Transitions API. So did Dave:

I think the most telling predictor for the success of the multi-page View Transitions API – compared to all other proposals and solutions that have come before it – is that I actually implemented this one. Despite animations being my bread and butter for many years, I couldn’t be arsed to even try any of the previous generation of tools.

Dave’s post is an excellent step-by-step introduction to using view transitions on your website. To recap:

Enable these two flags in Chrome Canary:

chrome://flags#view-transition
chrome://flags#view-transition-on-navigation

Then add this meta element to the head of your website:

<meta name="view-transition" content="same-origin">

You could stop there. If you navigate around your site, you’ll see that the navigations now fade in and out nicely from one page to another.

But the real power comes with transitioning page elements. Basically, you want to say “this element on this page should morph into that element on that page.” And when I say morph, I mean morph. As Dave puts it:

Behind the scenes the browser is rasterizing (read: making an image of) the before and after states of the DOM elements you’re transitioning. The browser figures out the differences between those two snapshots and tweens between them similar to Apple Keynote’s “Magic Morph” feature, the liquid metal T-1000 from Terminator 2: Judgement Day, or the 1980s cartoon series Turbo Teen.

If those references are lost on you, how about the popular kids book series Animorphs?

Some classic examples would be:

• A thumbnail of a video on one page morphs into the full-size video on the next page.
• A headline and snippet of an article on one page morphs into the full article on the next page.

I’ve added view transitions to The Session. Where I’ve got index pages with lists of titles, each title morphs into the heading on the next page.

Again, Dave’s post was really useful here. Each transition needs a unique name, so I used Dave’s trick of naming each transition with the ID of the individual item being linked to.

In the recordings section, for example, there might be a link like this on the index page:

<a href="/recordings/7812" style="view-transition-name: recording-7812">The Banks Of The Moy</a>

Which, if you click on it, takes you to the page with this heading:

<h1><span style="view-transition-name: recording-7812">The Banks Of The Moy</span></h1>

Why the span? Well, like Dave, I noticed some weird tweening happening between block and inline elements. Dave solved the problem with width: fit-content on the block-level element. I just stuck in an extra inline element.

Anyway, the important thing is that the name of the view transition matches: recording-7812.

I also added a view transition to pages that have maps. The position of the map might change from page to page. Now there’s a nice little animation as you move from one page with a map to another page with a map.

That’s all good, but I found myself wishing that I could just have those enhancements. Every single navigation on the site was triggering a fade in and out—the default animation. I wondered if there was a way to switch off the default fading.

There is! That default animation is happening on a view transition named root. You can get rid of it with this snippet of CSS:

::view-transition-image-pair(root) {
  isolation: auto;
}
::view-transition-old(root),
::view-transition-new(root) {
  animation: none;
  mix-blend-mode: normal;
  display: block;
}

Voila! Now only the view transitions that you name yourself will get applied.

You can adjust the timing, the easing, and the animation properites of your view transitions. Personally, I was happy with the default morph.

In fact, that’s one of the things I like about this API. It’s another good example of declarative design. I say what I want to happen, but I don’t need to specify the details. I’ll let the browser figure all that out.

That’s what’s got me so excited about this API. Yes, it’s powerful. But just as important, it’s got a very low barrier to entry.

Chris has gathered a bunch of examples together in his post Early Days Examples of View Transitions. Have a look around to get some ideas.

If you like what you see, I highly encourage you to add view transitions to your website now.

“But wait,” I hear you cry, “this isn’t supported in any public-facing browser yet!”

To which, I respond “So what?” It’s a perfect example of progressive enhancement. Adding one meta element and a smidgen of CSS will do absolutely no harm to your website. And while no-one will see your lovely view transitions yet, once browsers do start shipping with support for the API, your site will automatically get better.

Your website will be enhanced. Progressively.

Update: Simon Pieters quite rightly warns against adding view transitions to live sites before the API is done:

in general, using features before they ship in a browser isn’t a great idea since it can poison the feature with legacy content that might break when the feature is enabled. This has happened several times and renames or so were needed.

Good point. I must temper my excitement with pragmatism. Let me amend my advice:

I highly encourage you to experiment with view transitions on your website now.

The most cartoonish misrepresentation of progressive enhancement is that it means making everything work without JavaScript.

No. Progressive enhancement means making sure your core functionality works without JavaScript.

In my book Resilient Web Design, I quoted Wilto:

Lots of cool features on the Boston Globe don’t work when JS breaks; “reading the news” is not one of them.

That’s an example where the core functionality is readily identifiable. It’s a newspaper. The core functionality is reading the news.

It isn’t always so straightforward though. A lot of services that self-identify as “apps” will claim that even their core functionality requires JavaScript.

Surely I don’t expect Gmail or Google Docs to provide core functionality without JavaScript?

In those particular cases, I actually do. I believe that a textarea in a form would do the job nicely. But I get it. That might take a lot of re-engineering.

So how about this compromise…

Your app should work in a read-only mode without JavaScript.

Without JavaScript I should still be able to read my email in Gmail, even if you don’t let me compose, reply, or organise my messages.

Without JavaScript I should still be able to view a document in Google Docs, even if you don’t let me comment or edit the document.

Even with something as interactive as Figma or Photoshop, I think I should still be able to view a design file without JavaScript.

Making this distinction between read-only mode and read/write mode could be very useful, especially at the start of a project.

Begin by creating the read-only mode that doesn’t require JavaScript. That alone will make for a solid foundation to build upon. Now you’ve built a fallback for any unexpected failures.

Now start adding the read/write functionally. You’re enhancing what’s already there. Progressively.

Heck, you might even find some opportunities to provide some read/write functionality that doesn’t require JavaScript. But if JavaScript is needed, that’s absolutely fine.

So if you’re about to build a web app and you’re pretty sure it requires JavaScript, why not pause and consider whether you can provide a read-only version.

Robin penned a little love letter to the details element. I agree. It is a joyous piece of declarative power.

That said, don’t go overboard with it. It’s not a drop-in replacement for more complex widgets. But it is a handy encapsulation of straightforward progressive disclosure.

Just last week I added a couple of more details elements to The Session …kind of. There’s a bit of server-side conditional logic involved to determine whether details is the right element.

When you’re looking at a tune, one of the pieces of information you see is how many recordings there of that tune. Now if there are a lot of recordings, then there’s some additional information about which other tunes this one gets recorded with. That information is extra. Mere details, if you will.

You can see it in action on this tune listing. Thanks to the details element, the extra information is available to those who want it, but by default that information is tucked away—very handy for not clogging up that part of the page.

<details>
<summary>There are 181 recordings of this tune.</summary>
This tune has been recorded together with
<ul>
<li>…</li>
<li>…</li>
<li>…</li>
</ul>
</details>

Likewise, each tune page includes any aliases for the tune (in Irish music, the same tune can have many different titles—and the same title can be attached to many different tunes). If a tune has just a handful of aliases, they’re displayed in situ. But once you start listing out more than twenty names, it gets overwhelming.

The details element rides to the rescue once again.

Compare the tune I mentioned above, which only has a few aliases, to another tune that is known by many names.

Again, the main gist is immediately available to everyone—how many aliases are there? But if you want to go through them all, you can toggle that details element open.

You can effectively think of the summary element as the TL;DR of HTML.

<details>
<summary>There are 31 other names for this tune.</summary>
<p>Also known as…</p>
</details>

There’s another classic use of the details element: frequently asked questions. In the case of The Session, I’ve marked up the house rules and FAQs inside details elements, with the rule or question as the summary.

But there’s one house rule that’s most important (“Be civil”) so that details element gets an additional open attribute.

<details open>
<summary>Be civil</summary>
<p>Contributions should be constructive and polite, not mean-spirited or contributed with the intention of causing trouble.</p>
</details>

Push notifications are finally arriving on iOS—hallelujah! Like I said last year, this is my number one wish for the iPhone, though not because I personally ever plan to use the feature:

When I’m evangelising the benefits of building on the open web instead of making separate iOS and Android apps, I inevitably get asked about notifications. As long as mobile Safari doesn’t support them—even though desktop Safari does—I’m somewhat stumped. There’s no polyfill for this feature other than building an entire native app, which is a bit extreme as polyfills go.

With push notifications in mobile Safari, the arguments for making proprietary apps get weaker. That’s good.

The announcement post is a bit weird though. It never uses the phrase “progressive web apps”, even though clearly the entire article is all about progressive web apps. I don’t know if this down to Not-Invented-Here syndrome by the Apple/Webkit team, or because of genuine legal concerns around using the phrase.

Instead, there are repeated references to “Home Screen apps”. This distinction makes some sense though. In order to use web push on iOS, your website needs to be added to the home screen.

I think that would be fair enough, if it weren’t for the fact that adding a website to the home screen remains such a hidden feature that even power users would be forgiven for not knowing about it. I described the steps here:

1. Tap the “share” icon. It’s not labelled “share.” It’s a square with an arrow coming out of the top of it.
2. A drawer pops up. The option to “add to home screen” is nowhere to be seen. You have to pull the drawer up further to see the hidden options.
3. Now you must find “add to home screen” in the list

• Copy
• Add to Reading List
• Add Bookmark
• Add to Favourites
• Find on Page
• Add to Home Screen
• Markup
• Print

As long as this remains the case, we can expect usage of web push on iOS to be vanishingly low. Hardly anyone is going to add a website to their home screen when their web browser makes it so hard.

If you’d like to people to install your progressive web app, you’ll almost certainly need to prompt people to do so. Here’s the page I made on thesession.org with instructions on how to add to home screen. I link to it from the home page of the site.

I wish that pages like that weren’t necessary. It’s not the best user experience. But as long as mobile Safari continues to bury the home screen option, we don’t have much choice but to tackle this ourselves.

I was chatting with my new colleague Alex yesterday about a link she had shared in Slack. It was the Nielsen Norman Group’s annual State of Mobile User Experience report.

There’s nothing too surprising in there, other than the mention of Apple’s app clips and Google’s instant apps.

Remember those?

Me neither.

Perhaps I lead a sheltered existence, but as an iPhone user, I don’t think I’ve come across a single app clip in the wild.

I remember when they were announced. I was quite worried about them.

See, the one thing that the web can (theoretically) offer that native can’t is instant access to a resource. Go to this URL—that’s it. Whereas for a native app, the flow is: go to this app store, find the app, download the app.

(I say that the benefit is theoretical because the website found at the URL should download quickly—the reality is that the bloat of “modern” web development imperils that advantage.)

App clips—and instant apps—looked like a way to route around the convoluted install process of native apps. That’s why I was nervous when they were announced. They sounded like a threat to the web.

In reality, the potential was never fulfilled (if my own experience is anything to go by). I wonder why people didn’t jump on app clips and instant apps?

Perhaps it’s because what they promise isn’t desirable from a business perspective: “here’s a way for users to accomplish their tasks without downloading your app.” Even though app clips can in theory be a stepping stone to installing the full app, from a user’s perspective, their appeal is the exact opposite.

Or maybe they’re just too confusing to understand. I think there’s an another technology that suffers from the same problem: progressive web apps.

Hear me out. Progressive web apps are—if done well—absolutely amazing. You get all of the benefits of native apps in terms of UX—they even work offline!—but you retain the web’s frictionless access model: go to a URL; that’s it.

So what are they? Are they websites? Yes, sorta. Are they apps? Yes, sorta.

That’s confusing, right? I can see how app clips and instant apps sound equally confusing: “you can use them straight away, like going to a web page, but they’re not web pages; they’re little bits of apps.”

I’m mostly glad that app clips never took off. But I’m sad that progressive web apps haven’t taken off more. I suspect that their fates are intertwined. Neither suffer from technical limitations. The problem they both face is inertia:

The technologies are the easy bit. Getting people to re-evaluate their opinions about technologies? That’s the hard part.

True of progressive web apps. Equally true of app clips.

But when I was chatting to Alex, she made me look at app clips in a different way. She described a situation where somebody might need to interact with some kind of NFC beacon from their phone. Web NFC isn’t supported in many browsers yet, so you can’t rely on that. But you don’t want to make people download a native app just to have a quick interaction. In theory, an app clip—or instant app—could do the job.

In that situation, app clips aren’t a danger to the web—they’re polyfills for hardware APIs that the web doesn’t yet support!

I love having my perspective shifted like that.

The specific situations that Alex and I were discussing were in the context of museums. Musuems offer such interesting opportunities for the physical and the digital to intersect.

Remember the pen from Cooper Hewitt? Aaron spoke about it at dConstruct 2014—a terrific presentation that’s well worth revisiting and absorbing.

The other dConstruct talk that’s very relevant to this liminal space between the web and native apps is the 2012 talk from Scott Jenson. I always thought the physical web initiative had a lot of promise, but it may have been ahead of its time.

I loved the thinking behind the physical web beacons. They were deliberately dumb, much like the internet itself. All they did was broadcast a URL. That’s it. All the smarts were to be found at the URL itself. That meant a service could get smarter over time. It’s a lot easier to update a website than swap out a piece of hardware.

But any kind of technology that uses Bluetooth, NFC, or other wireless technology has to get over the discovery problem. They’re invisible technologies, so by default, people don’t know they’re even there. But if you make them too discoverable— intrusively announcing themselves like one of the commercials in Minority Report—then they’re indistinguishable from spam. There’s a sweet spot of discoverability right in the middle that’s hard to get right.

Over the past couple of years—accelerated by the physical distancing necessitated by The Situation—QR codes stepped up to the plate.

They still suffer from some discoverability issues. They’re not human-readable, so you can’t be entirely sure that the URL you’re going to go to isn’t going to be a Rick Astley video. But they are visible, which gives them an advantage over hidden wireless technologies.

They’re cheaper too. Printing a QR code sticker costs less than getting a plastic beacon shipped from China.

QR codes turned out to be just good enough to bridge the gap between the physical and digital for those one-off interactions like dining outdoors during a pandemic:

I can see why they chose the web over a native app. Online ordering is the only way to place your order at this place. Telling people “You have to go to this website” …that seems reasonable. But telling people “You have to download this app” …that’s too much friction.

Ironically, the nail in the coffin for app clips and instant apps might’ve been hammered in by Apple and Google when they built QR-code recognition into their camera software.

It’s been almost two years since I added audio playback on The Session. The interface is quite straightforward. For any tune setting, there’s a button that says “play audio”. When you press that button, audio plays and the button’s text changes to “pause audio.”

By updating the button’s text like this, I’m updating the button’s accessible name. In other situations, where the button text doesn’t change, you can indicate whether a button is active or not by toggling the aria-pressed attribute. I’ve been doing that on the “share” buttons that act as the interface for a progressive disclosure. The label on the button—“share”—doesn’t change when the button is pressed. For that kind of progressive disclosure pattern, the button also has an aria-controls and aria-expanded attribute.

From all the advice I’ve read about button states, you should either update the accessible name or change the aria-pressed attribute, but not both. That would lead to the confusing situation of having a button labelled “pause audio” as having a state of “pressed” when in fact the audio is playing.

That was all fine until I recently added some more functionality to The Session. As well as being able to play back audio, you can now adjust the tempo of the playback speed. The interface element for this is a slider, input type="range".

But this means that the “play audio” button now does two things. It plays the audio, but it also acts as a progressive disclosure control, revealing the tempo slider. The button is simultaneously a push button for playing and pausing music, and a toggle button for showing and hiding another interface element.

So should I be toggling the aria-pressed attribute now, even though the accessible name is changing? Or is it enough to have the relationship defined by aria-controls and the state defined by aria-expanded?

Based on past experience, my gut feeling is that I’m probably using too much ARIA. Maybe it’s an anti-pattern to use both aria-expanded and aria-pressed on a progressive disclosure control.

I’m kind of rubber-ducking here, and now that I’ve written down what I’m thinking, I’m pretty sure I’m going to remove the toggling of aria-pressed in any situation where I’m already toggling aria-expanded.

What I really need to do is enlist the help of actual screen reader users. There are a number of members of The Session who use screen readers. I should get in touch and see if the new functionality makes sense to them.

I’ve mentioned before that I don’t enable notifications on my phone. Text messages are the only exception. I don’t want to get notified if a new email arrives (I avoid email on my phone completely) and I certainly don’t want some social media app telling me somebody liked or faved something.

But the number one feature I’d like to see in Safari on iOS is web notifications.

It’s not for me personally, see. It’s because it’s the number one reason why people are choosing not to go all in progressive web apps.

Safari on iOS is the last holdout. But that equates to enough marketshare that many companies feel they can’t treat notifications as a progressive enhancement. While I may not agree with that decision myself, I get it.

When I’m evangelising the benefits of building on the open web instead of making separate iOS and Android apps, I inevitably get asked about notifications. As long as mobile Safari doesn’t support them—even though desktop Safari does—I’m somewhat stumped. There’s no polyfill for this feature other than building an entire native app, which is a bit extreme as polyfills go.

And of course, unlike on your Mac, you don’t have the option of using a different browser on your iPhone. As long as mobile Safari doesn’t support web notifications, nothing on iOS can support web notifications.

I’ve got progressive web apps on the home screen of my phone that match their native equivalents feature-for-feature. Twitter. Instagram. They’re really good. In some ways they’re superior to the native apps; the Twitter website is much calmer, and the Instagram website has no advertising. But if I wanted to get notifications from any of those sites, I’d have to keep the native apps installed just for that one feature.

So in the spirit of complaining about web browsers in a productive way, I just want to throw this plea out there: Apple, please support web notifications in mobile Safari!

The good news is that web notifications on iOS might be on their way. Huzzah!

Alas, we’re reliant on Maximiliano’s detective work to even get a glimpse of a future feature like this. Apple has no public roadmap for Safari. There’s this status page on the Webkit blog but it’s incomplete—web notifications don’t appear at all. In any case, WebKit and Safari aren’t the same thing. The only way of knowing if a feature might be implemented in Safari is if it shows up in Safari Technology Preview, at which point it’s already pretty far along.

So while my number one feature request for mobile Safari is web notifications, a close second would be a public roadmap.

It only seems fair. If Apple devrels are asking us developers what features we’d like to see implemented—as they should!—then shouldn’t those same developers also be treated with enough respect to share a roadmap with them? There’s not much point in us asking for features if, unbeknownst to us, that feature is already being worked on.

But, like I said, my number one request remains: web notifications on iOS …please!

Dave recently wrote some good advice about what to do—and what not to do—when it comes to complaining about web browsers. I wrote something on this topic a little while back:

If there’s something about a web browser that you’re not happy with (or, indeed, if there’s something you’re really happy with), take the time to write it down and publish it

To summarise Dave’s advice, avoid conspiracy theories and snark; stick to specifics instead.

It’s very good advice that I should heed (especially the bit about avoiding snark). In that spirit, I’d like to document what I think is a bug on iOS.

I don’t need to name the specific browser, because there is basically only one browser allowed on iOS. That’s not snark; that’s a statement of fact.

This bug involves navigating from a progressive web app that has been installed on your home screen to an external web view.

To illustrate the bug, I’ll use the example of The Session. If you want to recreate the bug, you’ll need to have an account on The Session. Let me know if you want to set up a temporary account—I can take care of deleting it afterwards.

Here are the steps:

1. Navigate to thesession.org in Safari on an iOS device.
2. Add the site to your home screen.
3. Open the installed site from your home screen—it will launch in standalone mode.
4. Log in with your username and password.
5. Using the site menu, navigate to the links section of the site.
6. Click on any external link.
7. After the external link opens in a web view, tap on “Done” to close the web view.

Expected behaviour: you are returned to the page you were on with no change of state.

Actual behaviour: you are returned to the page you were on but you are logged out.

So the act of visiting an external link in a web view while in a progressive web app in standalone mode seems to cause a loss of cookie-based authentication.

This isn’t permanent. Clicking on any internal link restores the logged-in state.

It is surprising though. My mental model for opening an external link in a web view is that it sits “above” the progressive web app, which remains in stasis “behind” it. But the page must actually be reloading, either when the web view is opened or when the web view is closed. And that reload is behaving like a fetch event without credentials.

Anyway, that’s my bug report. It may already be listed somewhere on the WebKit Bugzilla but I lack the deductive skills to find it. I’m not even sure if that’s the right place for this kind of bug. It might be specific to the operating system rather than the rendering engine.

This isn’t a high priority bug, but it is one of those cumulatively annoying software paper cuts.

Hope this helps!

I wrote about how I created a page on The Session with instructions for installing the site to your home screen. When I said that I included screenshots on that page, I may have underplayed the effort involved. It was real faff.

I’ve got an iPhone so generating screenshots (and video) from that wasn’t too bad. But I don’t have access to an Android phone. I found myself scouring the web for templates that I could use to mockup a screenshot of the address bar.

That got me thinking…

Wouldn’t it be cool if there were a service that generated those screenshots for you? You give it a URL, and it spits out screenshots of the site complete with overlays showing the installation flow on Android and iOS. It could even generate the img markup, complete with differently-scaled images for the srcset attribute.

Download the images. Copy that markup. Paste it into a page on your site. Boom! Now you’ve got somewhere to point your visitors to if you’d like them to install your progressive web app.

There are already some services out there for generating screenshots of mobile phones but they’re missing is the menu overlays for adding to home screen.

The devrels at both Google and Microsoft have been doing a great job of promoting progressive web apps. They’ve built tools to help you with tasks like generating icons or creating your web app manifest. It would be sooooo nifty if those tools also generated instructional screenshots for adding to home screen!

I don’t know about you, but it seems like everyone I follow on Twitter is playing Wordle. Although I don’t play the game myself, I think it’s pretty great.

Not only does Wordle have a very sweet backstory, but it’s also unashamedly on the web. If you want to play, you go to the URL powerlanguage.co.uk/wordle. That’s it. No need to download an app.

That hasn’t stopped some nefarious developers trying to trick people into downloading their clones of Wordle from app stores. App stores, which are meant to be curated and safe, are in fact filled with dodgy knock-offs and scams. Contrary to popular belief, the web is quite literally a safer bet.

Wordle has a web app manifest, which means you can add it to your home screen and it will behave just like a native app (although I don’t believe it has offline support). That’s great, but the process of adding a web app to your home screen on iOS is ludicrously long-winded.

Macworld published an article detailing how to get the real Wordle app on your iPhone or iPad. On the one hand it’s great to see this knowledge being spread. On the other hand it’s dispiriting that it’s even necessary to tell people that they can do this, like it’s a hidden nerdy secret just for power users.

At this point I’ve pretty much given up on Apple ever doing anything about this pathetic situation. So what can I do instead?

Well, taking my cue from that Macworld article, the least I can do is inform people how they can add a progressive web app to their home screen.

That’s what I’ve done on thesession.org. I’ve published a page on how to install The Session to your home screen.

On both Android and iPhone the journey to installing a progressive web app begins with incomprehensible iconography. On Android you must first tap on the unlabeled kebab icon—three vertical dots. On iOS you must first tap on the unlabeled share icon—a square with an arrow coming out of it.

When it comes to mobile operating systems, consumer choice means you choose which kind of mystery meat to eat.

I’ve included screenshots to help people identify these mysterious portals. For iOS I’ve also included a video to illustrate the quest to find the secret menu item buried beneath the share icon.

I’ve linked to the page with the installation instructions from the site’s “help” page and the home page.

Handy tip: when you’re adding a start_url value to your web app manifest, it’s common to include a query string like this:

start_url: "/?homescreen"

I’m guessing most people to that so they can get analytics on how many people are starting from an icon tap. I don’t do analytics on The Session but I’m still using that query string in my start_url. On the home page of the site, I check for the existence of the query string. If it exists, I don’t show the link to the installation page. So once someone has installed the site to their home screen, they shouldn’t see that message when they launch The Session.

If you’ve got a progressive web app, it might be worth making a page with installation instructions rather than relying on browsers to proactively inform your site’s visitors. You’d still need to figure out the right time and place to point people to that page, but at least the design challenge would be in your hands.

Should you decide to take a leaf out of the Android and iOS playbooks and use mystery meat navigation to link to such a page, there’s an emoji you could potentially use: 📲

It’s still worse than using actual words, but it might be better than some random combination of dots, squares and arrows.

(I’m not really serious about using that emoji, but if you do, be sure to use a sensible aria-label value on the enclosing a element.)