Journal tags: standards

146

sparkline

Jake Archibald is speaking at Web Day Out

I’m very happy to announce that the one and only Jake Jaffa-The-Cake Archibald will be speaking at Web Day Out!

Given the agenda for this event, I think you’ll agree that Jake is a perfect fit. He’s been at the forefront of championing user-centred web standards, writing specs and shipping features in browsers.

Along the way he’s also created two valuable performance tools that I use all the time: SVGOMG and Squoosh, which has a permanent place in my dock—if you need to compress images, I highly recommend adding this progressive web app to your desktop.

He’s the man behind service workers and view transitions—two of the most important features for making websites first-class citizens on any device.

So what will he talk about at Web Day Out? Image formats? Offline functionality? Smooth animations? Something else entirely?

All will be revealed soon. In the meantime, grab yourself a ticket to Web Day Out—it’s just £225+VAT—and I’ll see you in Brighton on Thursday, 12 March 2026!

Reasoning

Tim recently gave a talk at Smashing Conference in New York called One Step Ahead. Based on the slides, it looks like it was an excellent talk.

Towards the end, there’s a slide that could be the tagline for Web Day Out:

Betting on the browser is our best chance at long-term success.

Most of the talk focuses on two technologies that you can add to any website with just a couple of lines of code: view transitions and speculation rules.

I’m using both of them on The Session and I can testify to their superpowers—super-snappy navigations with smooth animations.

Honestly, that takes care of 95% of the reasons for building a single-page app (the other 5% would be around managing state, which most sites—e-commerce, publishing, whatever—don’t need to bother with). Instead build a good ol’-fashioned website with pages of HTML linked together, then apply view transitions and speculation rules.

I mean, why wouldn’t you do that?

That’s not a rhetorical question. I’m genuinely interested in the reasons why people would reject a simple declarative solution in favour of the complexity of doing everything with a big JavaScript framework.

One reason might be browser support. After all, both view transitions and speculation rules are designed to be used as progressive enhancements, regardless of how many browsers happen to support them right now. If you want to attempt to have complete control, I understand why you might reach for the single-page app model, even if it means bloating the initial payload.

But think about that mindset for a second. Rather than reward the browsers that support modern features, you would instead be punishing them. You’d be treating every browser the same. Instead of taking advantage of the amazing features that some browsers have, you’d rather act as though they’re no different to legacy browsers.

I kind of understand the thinking behind that. You assume a level playing field by treating every browser as though they’re Internet Explorer. But what a waste! You ship tons of uneccesary code to perfectly capable browsers.

That could be the tagline for React.

Simplify

I was messing about with some images on a website recently and while I was happy enough with the arrangement on large screens, I thought it would be better to have the images in a kind of carousel on smaller screens—a swipable gallery.

My old brain immediately thought this would be fairly complicated to do, but actually it’s ludicrously straightforward. Just stick this bit of CSS on the containing element inside a media query (or better yet, a container query):

display: flex;
overflow-x: auto;

That’s it.

Oh, and you can swap out overflow-x for overflow-inline if, like me, you’re a fan of logical properties. But support for that only just landed in Safari so I’d probably wait a little while before removing the old syntax.

Here’s an example using pictures of some of the lovely people who will be speaking at Web Day Out:

Jemima Abu Rachel Andrew Lola Odelola Richard Rutter Harry Roberts

While you’re at it, add this:

overscroll-behavior-inline: contain;

Thats prevents the user accidentally triggering a backwards/forwards navigation when they’re swiping.

You could add some more little niceties like this, but you don’t have to:

scroll-snap-type: inline mandatory;
scroll-behavior: smooth;

And maybe this on the individual items:

scroll-snap-align: center;

You could progressively enhance even more with the new pseudo-elements like ::scroll-button() and ::scroll-marker for Chromium browsers.

Apart from that last bit, none of this is particularly new or groundbreaking. But it was a pleasant reminder for me that interactions that used to be complicated to implement are now very straightforward indeed.

Here’s another example that Ana Tudor brought up yesterday:

You have a section with a p on the left & an img on the right. How do you make the img height always be determined by the p with the tiniest bit of CSS? 😼

No changing the HTML structure in any way, no pseudos, no background declarations, no JS. Just a tiny bit of #CSS.

Old me would’ve said it can’t be done. But with a little bit of investigating, I found a nice straightforward solution:

section >  img {
  contain: size;
  place-self: stretch;
  object-fit: cover;
}

That’ll work whether the section has its display set to flex or grid.

There’s something very, very satisfying in finding a simple solution to something you thought would be complicated.

Honestly, I feel like web developers are constantly being gaslit into thinking that complex over-engineered solutions are the only option. When the discourse is being dominated by people invested in frameworks and libraries, all our default thinking will involve frameworks and libraries. That’s not good for users, and I don’t think it’s good for us either.

Of course, the trick is knowing that the simpler solution exists. The information probably isn’t going to fall in your lap—especially when the discourse is dominated by overly-complex JavaScript.

So get yourself a ticket for Web Day Out. It’s on Thursday, March 12th, 2026 right here in Brighton.

I guarantee you’ll hear about some magnificent techniques that will allow you to rip out plenty of complex code in favour of letting the browser do the work.

Speaking at Web Day Out

Half of the line-up of speakers for Web Day Out is already on the site. One more is already confirmed.

I’m ridiculously excited about the way the line-up is taking shape, and judging by the zippiness of ticket sales, so are lots of my peers. Seriously, don’t wait to get your ticket or you might end up missing out completely.

I’ve already got a shortlist of other people I could imagine on the line-up, but I’m open to more suggestions. If you’d like to speak at Web Day Out—or you know someone you think would be great—send an email to jeremy@clearleft.com

I won’t be checking my work email while I’m away on holiday next week but it would be lovely to come back to an inbox of exciting suggestions.

A couple of pointers…

I’d rather not have too many people like me on the line-up. White dudes are already over-represented in this industry, especially at conferences.

If you’ve never given a talk before, don’t worry. I’d love to help you put your talk together and coach you in presenting it. I have some experience in this area.

No product pitches. That includes JavaScript frameworks and CSS libraries.

If I get even a whiff of “AI”, your proposal doesn’t stand a chance. There are many, many, many other events that are only too happy to have wall-to-wall talks about …that sort of thing.

If you end up speaking at Web Day Out you will, of course, be paid. We will, of course, cover travel and accommodation too. We can’t afford the travel costs of bringing anyone in from outside Europe though (and we’d like to keep the carbon footprint of the event as small as possible).

Web Day Out has an opinionated agenda all about showing what’s possible in web browsers today. Some potential topics include:

The emphasis should be on using stuff in production rather than theoretical demos.

If you’ve got a case study about using the web platform—perhaps migrating away from a framework-driven approach—that would fit the bill perfectly.

How’s all that sounding? Know someone who could deliver the goods? Let me know!

Announcing Web Day Out

I’m going to cut right to the chase: Clearleft is putting on a brand new conference in 2026. It’s called Web Day Out. It’ll be on Thursday, March 12th right here in Brighton. Tickets are just £225+VAT. You should be there!

If you’ve ever been to Responsive Day Out or Patterns Day, the format will be familiar to you. There’s going to be eight 30 minute talks. Bam! Bam! Bam!

Like those other one-day conferences, this one has a laser-sharp focus.

Web Day Out is all about what you can do in web browsers today. You can expect talks that showcase hands-on practical uses for the latest advances in HTML, CSS, and JavaScript APIs. There will be no talks about libraries, frameworks or build tools, and I can guarantee there will be absolutely no so-called “AI”.

As you might have gathered, this is an opinionated conference.

If you care about performance, accessibility, and progressive enhancement, Web Day Out is the event for you.

Or if you’ve been living in React-land but starting to feel that maybe you’re missing out on what’s been shipping in web browsers, Web Day Out is the event for you too. And I’m not talking about cute demos here. This is very much about shipping to production.

I’ve got half of the line-up assembled already:

Jemima’s talk gives you a flavour of what to expect at Web Day Out:

In this talk, we’ll take a look at how to use HTML and CSS to build simpler alternatives to popular JavaScript components such as accordions, modals, scroll transitions, carousels etc We’ll also take a look at the performance and accessibility benefits and real-life applications and use-cases of these components.

Web Day Out will be in The Studio Theatre of the Brighton Dome, which is a fantastic intimate venue. That means that places are limited, so get your ticket now!

Command and control

I’ve been banging on for a while now about how much I’d like a declarative option for the Web Share API. I was thinking that the type attribute on the button element would be a good candidate for this (there’s prior art in the way we extended the type attribute on the input element for HTML5).

I wrote about the reason for a share button type as well as creating a polyfill. I also wrote about how this idea would work for other button types: fullscreen, print, copy to clipboard, that sort of thing.

Since then, I’ve been very interested in the idea of “invokers” being pursued by the Open UI group. Rather than extending the type attribute, they’ve been looking at adding a new attribute. Initially it was called invoketarget (so something like button invoketarget="share").

Things have been rolling along and invoketarget has now become the command attribute (there’s also a new commandfor attribute that you can point to an element with an ID). Here’s a list of potential values for the command attribute on a button element.

Right now they’re focusing on providing declarative options for launching dialogs and other popovers. That’s already shipping.

The next step is to use command and commandfor for controlling audio and video, as well as some form controls. I very much approve! I love the idea of being able to build and style a fully-featured media player without any JavaScript.

I’m hoping that after that we’ll see the command attribute get expanded to cover JavaScript APIs that require a user interaction. These seem like the ideal candidates:

There’s also scope for declarative options for navigating the browser’s history stack:

  • button command="back"
  • button command="forward"
  • button command="refresh"

Whatever happens next, I’m very glad to see that so much thinking is being applied to declarative solutions for common interface patterns.

Style legend

There’s a new proposal for giving developers more control over styling form controls. I like it.

It’s clearly based on the fantastic work being done by the Open UI group on the select element. The proposal suggests that authors can opt-in to the new styling possibilities by declaring:

appearance: base;

So basically the developer is saying “I know what I’m doing—I’m taking the controls.” But browsers can continue to ship their default form styles. No existing content will break.

The idea is that once the developer has opted in, they can then style a number of pseudo-elements.

This proposal would apply to pretty much all the form controls you can think of: all the input types, along with select, progress, meter, buttons and more.

But there’s one element more that I wish were on the list:

legend

I know, technically it’s not a form control but legend and fieldset are only ever used within forms.

The legend element is notoriously annoying to style. So a lot of people just don’t bother using it, which is a real shame. It’s like we’re punishing people for doing the right thing.

Wouldn’t it be great if you, as a developer, had the option of saying “I know what I’m doing—I’m taking the controls”:

legend {
  appearance: base;
}

Imagine if that nuked the browser’s weird default styles, effectively turning the element into a span or div as far as styling is concerned. Then you could style it however you wanted. But crucially, if browsers shipped this, no existing content would break.

The shitty styling situation for legend (and its parent fieldset) is one of those long-standing annoyances that seems to have fallen down the back of the sofa of browser vendors. No one’s going to spend time working on it when there are more important newer features to ship. That’s why I’d love to see it sneak in to this new proposal for styling form controls.

I was in Amsterdam last week. Just like last year I was there to help out Vasilis’s students with a form-based assignment:

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.

(Side note: this time they were told to style it using the design system from the Dutch railway because the tax office was getting worried that they were making phishing sites.)

I saw a lot of the same challenges again. I saw how students wished they could specify a past date or a future date in a date picker without using JavaScript. And I saw them lamenting the time they spent styling legends that worked across all browsers.

Right now, Mason Freed has an open issue on the new proposal with his suggestion to add some more elements to consider. Both legend and fieldset are included. That gets a thumbs-up from me.

The web on mobile

Here’s a post outlining all the great things you can do in mobile web browsers today: Your App Should Have Been A Website (And Probably Your Game Too):

Today’s browsers are powerhouses. Notifications? Check. Offline mode? Check. Secure payments? Yep, they’ve got that too. And with technologies like WebAssembly and WebGPU, web games are catching up to native-level performance. In some cases, they’re already there.

This is all true. But this post from John Gruber is equally true: One Bit of Anecdata That the Web Is Languishing Vis-à-Vis Native Mobile Apps:

I won’t hold up this one experience as a sign that the web is dying, but it sure seems to be languishing, especially for mobile devices.

As John points out, the problems aren’t technical:

There’s absolutely no reason the mobile web experience shouldn’t be fast, reliable, well-designed, and keep you logged in. If one of the two should suck, it should be the app that sucks and the website that works well. You shouldn’t be expected to carry around a bundle of software from your utility company in your pocket. But it’s the other way around.

He’s right. It makes no sense, but this is the reality.

Ten or fifteen years ago, the gap between the web and native apps on mobile was entirely technical. There were certain things that you just couldn’t do in web browsers. That’s no longer the case now. The web caught up quite a while back.

But the experience of using websites on a mobile device is awful. Never mind the terrible performance penalties incurred by unnecessary frameworks and libraries like React and its ilk, there’s the constant game of whack-a-mole with banners and overlays. What’s just about bearable in a large desktop viewport becomes intolerable on a small screen.

This is not a technical problem. This doesn’t get solved by web standards. This is a cultural problem.

First of all, there’s the business culture. If your business model depends on tracking people or pushing newsletter sign-ups, then it’s inevitable that your website will be shite on mobile.

Mind you, if your business model depends on tracking people, you’re more likely to try push people to download your native app. Like Cory Doctorow says:

50% of web users are running ad-blockers. 0% of app users are running ad-blockers, because adding a blocker to an app requires that you first remove its encryption, and that’s a felony (Jay Freeman calls this ‘felony contempt of business-model’).

Matt May brings up the same point in his guide, How to grey-rock Meta:

Remove Meta apps from your devices and use only the mobile web versions. Mobile apps have greater access to your personal data, provided the app requests those privileges, and Facebook and Instagram in particular (more so than WhatsApp, another Meta property) request the vast majority of those privileges. This includes precise GPS data on where you are, whether or not you are using the app.

Ironically, it’s the strength of the web—and web browsers—that has led to such shitty mobile web experiences. The pretty decent security model on the web means that sites have to pester you.

Part of the reason why you don’t see the same egregious over-use of pop-ups and overlays in native apps is that they aren’t needed. If you’ve installed the app, you’re already being tracked.

But when I describe the dreadful UX of most websites on mobile as a cultural problem, I don’t just mean business culture.

Us, the people who make websites, designers and developers, we’re responsible for this too.

For all our talk of mobile-first design for the last fifteen years, we never really meant it, did we? Sure, we use media queries and other responsive techniques, but all we’ve really done is make sure that a terrible experience fits on the screen.

As developers, I’m sure we can tell ourselves all sorts of fairy tales about why it’s perfectly justified to make users on mobile networks download React, Tailwind, and megabytes more of third-party code.

As designers, I’m sure we can tell ourselves all sorts of fairy tales about why intrusive pop-ups and overlays are the responsibility of some other department (as though users make any sort of distinction).

Worst of all, we’ve spent the last fifteen years teaching users that if they want a good experience on their mobile device, they should look in an app store, not on the web.

Ask anyone about their experience of using websites on their mobile device. They’ll tell you plenty of stories of how badly it sucks.

It doesn’t matter that the web is the perfect medium for just-in-time delivery of information. It doesn’t matter that web browsers can now do just about everything that native apps can do.

In many ways, I wish this were a technical problem. At least then we could lobby for some technical advancement that would fix this situation.

But this is not a technical problem. This is a people problem. Specifically, the people who make websites.

We fucked up. Badly. And I don’t see any signs that things are going to change anytime soon.

But hey, websites on desktop are just great!

Making the new Salter Cane website

With the release of a new Salter Cane album I figured it was high time to update the design of the band’s website.

Here’s the old version for reference. As you can see, there’s a connection there in some of the design language. Even so, I decided to start completely from scratch.

I opened up a text editor and started writing HTML by hand. Same for the CSS. No templates. No build tools. No pipeline. Nothing. It was a blast!

And lest you think that sounds like a wasteful way of working, I pretty much had the website done in half a day.

Partly that’s because you can do so much with so little in CSS these days. Custom properties for colours, spacing, and fluid typography (thanks to Utopia). Logical properties. View transitions. None of this takes much time at all.

Because I was using custom properties, it was a breeze to add a dark mode with prefers-color-scheme. I think I might like the dark version more than the default.

The final stylesheet is pretty short. I didn’t bother with any resets. Browsers are pretty consistent with their default styles nowadays. As long as you’ve got some sensible settings on your body element, the cascade will take care of a lot.

There’s one little CSS trick I think is pretty clever…

The background image is this image. As you can see, it’s a rectangle that’s wider than it is tall. But the web pages are rectangles that are taller than they are wide.

So how I should I position the background image? Centred? Anchored to the top? Anchored to the bottom?

If you open up the website in Chrome (or Safari Technical Preview), you’ll see that the background image is anchored to the top. But if you scroll down you’ll see that the background image is now anchored to the bottom. The background position has changed somehow.

This isn’t just on the home page. On any page, no matter how tall it is, the background image is anchored to the top when the top of the document is in the viewport, and it’s anchored to the bottom when you reach the bottom of the document.

In the past, this kind of thing might’ve been possible with some clever JavaScript that measured the height of the document and updated the background position every time a scroll event is triggered.

But I didn’t need any JavaScript. This is a scroll-driven animation made with just a few lines of CSS.

@keyframes parallax {
    from {
        background-position: top center;
    }
    to {
        background-position: bottom center;
    }
}
@media (prefers-reduced-motion: no-preference) {
        html {
            animation: parallax auto ease;
            animation-timeline: scroll();
        }
    }
}

This works as a nice bit of progressive enhancement: by default the background image stays anchored to the top of the viewport, which is fine.

Once the site was ready, I spent a bit more time sweating some details, like the responsive images on the home page.

But the biggest performance challenge wasn’t something I had direct control over. There’s a Spotify embed on the home page. Ain’t no party like a third party.

I could put loading="lazy" on the iframe but in this case, it’s pretty close to the top of document so it’s still going to start loading at the same time as some of my first-party assets.

I decided to try a little JavaScript library called “lazysizes”. Normally this would ring alarm bells for me: solving a problem with third-party code by adding …more third-party code. But in this case, it really did the trick. The library is loading asynchronously (so it doesn’t interfere with the more important assets) and only then does it start populating the iframe.

This made a huge difference. The core web vitals went from being abysmal to being perfect.

I’m pretty pleased with how the new website turned out.

Web App install API

My bug report on Apple’s websites-in-the-dock feature on desktop has me thinking about how starkly different it is on mobile.

On iOS if you want to add a website to your home screen, good luck. The option is buried within the “share” menu.

First off, it makes no sense that adding something to your homescreen counts as sharing. Secondly, how is anybody supposed to know that unless they’re explicitly told.

It’s a similar situation on Android. In theory you can prompt the user to install a progressive web app using the botched BeforeInstallPromptEvent. In practice it’s a mess. What it actually does is defer the installation prompt so you can offer it a more suitable time. But it only works if the browser was going to offer an installation prompt anyway.

When does Chrome on Android decide to offer the installation prompt? It’s a mix of required criteria—a web app manifest, some icons—and an algorithmic spell determined by the user’s engagement.

Other browser makers don’t agree with this arbitrary set of criteria. They quite rightly say that a user should be able to add any website to their home screen if they want to.

What we really need is an installation API: a way to programmatically invoke the add-to-homescreen flow.

Now, I know what you’re going to say. The security and UX implications would be dire. But this should obviously be like geolocation or notifications, only available in secure contexts and gated by user interaction.

Think of it like adding something to the clipboard: it’s something the user can do manually, but the API offers a way to do it programmatically without opening it up to abuse.

(I’d really love it if this API also had a declarative equivalent, much like I want button type="share" for the Web Share API. How about button type="install"?)

People expect this to already exist.

The beforeinstallprompt flow is an absolute mess. Users deserve better.

CSS Day 2024

My stint as one of the hosts of CSS Day went very well indeed. I enjoyed myself and people seemed to like the cut of my jib.

During the event there was a real buzz on Mastodon, which was heartening to see. I was beginning to worry that hashtagging events was going to be collatoral damage from Elongate, but there was plenty of conference-induced FOMO to be experienced on the fediverse.

The event itself was, as always, excellent. Both in terms of content and organisation.

Some themes emerged during CSS Day, which I always love to see. These emergent properties are partly down to curation and partly down to serendipity.

The last few years of CSS Day have felt like getting a firehose of astonishing new features being added to the language. There was still plenty of cutting-edge stuff this year—masonry! anchor positioning!—but there was also a feeling of consolidation, asking how to get all this amazing new stuff into our workflows.

Matthias’s opening talk on day one and Stephen’s closing talk on the same day complemented one another perfectly. Both managed to inspire while looking into the nitty-gritty practicalities of the web design process.

It was, astoundingly, Matthias’s first ever conference talk. I have no doubt it won’t be the last—it was great!

I gave Stephen a good-natured roast in my introduction, partly because it was his birthday, partly because we’re old friends, but mostly because it was enjoyable for me to watch him squirm. Of course his talk was, as always, superb. Don’t tell him, but he might be one of my favourite speakers.

The topic of graphic design tools came up more than once. It’s interesting to see how the issues with them have changed. It used to be that design tools—Photoshop, Sketch, Figma—were frustrating because they were writing cheques that CSS couldn’t cash. Now the frustration is the exact opposite. Our graphic design tools aren’t capable of the kind of fluid declarative design we can now accomplish in web browsers.

But the biggest rift remains not with tools or technologies, but with people and mindsets. Our tools can reinforce mindsets but the real divide happens in how different people approach CSS.

Both Josh and Kevin get to the heart of this in their tremendous tutorials, and that was reflected in their talks. They showed the difference between having the bare minimum understanding of CSS in order to get something done as quickly as possible, and truly understanding how CSS works in order to open up a world of possibilities.

For people in the first category, Sarah Dayan was there to sing the praises of utility-first CSS AKA atomic CSS. I commend her bravery!

During the Q&A, I restrained myself from being too Paxmanish. But I did have l’esprit d’escalier afterwards when I realised that the entire talk—and all the answers afterwards—depended on two mutually-incompatiable claims:

  1. The great thing about atomic CSS is that it’s a constrained vocabulary so your team has to conform, and
  2. The other great thing about it is that it’s utility-first, not utility-only so you can break out of it and use regular CSS if you want.

Insert .gif of character from The Office looking to camera.

Most of the questions coming in during the Q&A reflected my own take: how about we use utility classes for some things, but not all things. Seems sensible.

Anyway, regardless of what I or anyone else thinks about the substance of what Sarah was saying, there was no denying that it was a great presentation. They were all great presentations. That’s unusual, and I say that as a conference organiser as well as an attendee. Everyone brings their A-game to CSS Day.

Mind you, it is exhausting. I say it every year, but it always feels like one talk too many. Not that any individual talk wasn’t good, but the sheer onslaught of deep dives into the innards of CSS has my brain exploding before the day is done.

A highlight for me was getting to introduce Fantasai’s talk on the design principles of CSS, which was right up my alley. I don’t think most people realise just how much we owe her for her years of work on standards. The web would be in a worse place without the Herculean work she’s done behind the scenes.

Another highlight was getting to see some of the students I met back in March. They were showing some of their excellent work during the breaks. I find what they’re doing just as inspiring as the speakers on stage.

In fact, when I was filling in the post-conference feedback form, there was a question: “Who would you like to see speak at CSS Day next year?” I was racking my brains because everyone I could immediately think of has already spoken at some point. So I wrote, “It would be great to see some of those students speaking about their work.”

I think it would be genuinely fascinating to get their perspective on what we consider modern CSS, which to them is just CSS.

Either way I’ll back next year for sure.

It’s funny, but usually when a conference is described as “inspiring” it’s because it’s tackling big galaxy-brain questions. But CSS Day is as nitty-gritty as it gets and I found it truly inspiring. Like, I couldn’t wait to open up my laptop and start writing some CSS. That kind of inspiring.

Browser support

There was a discussion at Clearleft recently about browser support. Rich has more details but the gist of it is that, even though we were confident that we had a good approach to browser support, we hadn’t written it down anywhere. Time to fix that.

This is something I had been thinking about recently anyway—see my post about Baseline and progressive enhancement—so it didn’t take too long to put together a document explaining our approach.

You can find it at browsersupport.clearleft.com

We’re not just making it public. We’re releasing it under a Creative Commons attribution license. You can copy this browser-support policy verbatim, you can tweak it, you can change it, you can do what you like. As long you include a credit to Clearleft, you’re all set.

I think this browser-support policy makes a lot of sense. It certainly beats trying to browser support to specific browsers or version numbers:

We don’t base our browser support on specific browser names and numbers. Instead, our support policy is based on the capabilities of those browsers.

The more organisations adopt this approach, the better it is for everyone. Hence the liberal licensing.

So next time your boss or your client is asking what your official browser-support policy is, feel free to use browsersupport.clearleft.com

Speculation rules and fears

After I wrote positively about the speculation rules API I got an email from David Cizek with some legitimate concerns. He said:

I think that this kind of feature is not good, because someone else (web publisher) decides that I (my connection, browser, device) have to do work that very often is not needed. All that blurred by blackbox algorithm in the browser.

That’s fair. My hope is that the user will indeed get more say, whether that’s at the level of the browser or the operating system. I’m thinking of a prefers-reduced-data setting, much like prefers-color-scheme or prefers-reduced-motion.

But this issue isn’t something new with speculation rules. We’ve already got service workers, which allow the site author to unilaterally declare that a bunch of pages should be downloaded.

I’m doing that for Resilient Web Design—when you visit the home page, a service worker downloads the whole site. I can justify that decision to myself because the entire site is still smaller in size than one article from Wired or the New York Times. But still, is it right that I get to make that call?

So I’m very much in favour of browsers acting as true user agents—doing what’s best for the user, even in situations where that conflicts with the wishes of a site owner.

Going back to speculation rules, David asked:

Do we really need this kind of (easily turned to evil) enhancement in the current state of (web) affairs?

That question could be asked of many web technologies.

There’s always going to be a tension with any powerful browser feature. The more power it provides, the more it can be abused. Animations, service workers, speculation rules—these are all things that can be used to improve websites or they can be abused to do things the user never asked for.

Or take the elephant in the room: JavaScript.

Right now, a site owner can link to a JavaScript file that’s tens of megabytes in size, and the browser has no alternative but to download it. I’d love it if users could specify a limit. I’d love it even more if browsers shipped with a default limit, especially if that limit is related to the device and network.

I don’t think speculation rules will be abused nearly as much as client-side JavaScript is already abused.

Speculation rules

There’s a new addition to the latest version of Chrome called speculation rules. This already existed before with a different syntax, but the new version makes more sense to me.

Notice that I called this an addition, not a standard. This is not a web standard, though it may become one in the future. Or it may not. It may wither on the vine and disappear (like most things that come from Google).

The gist of it is that you give the browser one or more URLs that the user is likely to navigate to. The browser can then pre-fetch or even pre-render those links, making that navigation really snappy. It’s a replacement for the abandoned link rel="prerender".

Because this is a unilateral feature, I’m not keen on shipping the code to all browsers. The old version of the API required a script element with a type value of “speculationrules”. That doesn’t do any harm to browsers that don’t support it—it’s a progressive enhancement. But unlike other progressive enhancements, this isn’t something that will just start working in those other browsers one day. I mean, it might. But until this API is an actual web standard, there’s no guarantee.

That’s why I was pleased to see that the new version of the API allows you to use an external JSON file with your list of rules.

I say “rules”, but they’re really more like guidelines. The browser will make its own evaluation based on bandwidth, battery life, and other factors. This feature is more like srcset than source: you give the browser some options, but ultimately you can’t force it to do anything.

I’ve implemented this over on The Session. There’s a JSON file called speculationrules.js with the simplest of suggestions:

{
  "prerender": [{
    "where": {
        "href_matches": "/*"
    },
    "eagerness": "moderate"
  }]
}

The eagerness value of “moderate” says that any link can be pre-rendered if the user hovers over it for 200 milliseconds (the nuclear option would be to use a value of “immediate”).

I still need to point to that JSON file from my HTML. Usually this would be done with something like a link element, but for this particular API, I can send a response header instead:

Speculation-Rules: “/speculationrules.json"

I like that. The response header is being sent to every browser, regardless of whether they support speculation rules or not, but at least it’s just a few bytes. Those other browsers will ignore the header—they won’t download the JSON file.

Here’s the PHP I added to send that header:

header('Speculation-Rules: "/speculationrules.json"');

There’s one extra thing I had to do. The JSON file needs to be served with mime-type of “application/speculationrules+json”. Here’s how I set that up in the .conf file for The Session on Apache:

<IfModule mod_headers.c>
  <FilesMatch "speculationrules.json">
    Header set Content-type application/speculationrules+json
   </FilesMatch>
</IfModule>

A bit of a faff, that.

You can see it in action on The Session. Open up Chrome or Edge (same same but different), fire up the dev tools and keep the network tab open while you navigate around the site. Notice how hovering over a link will trigger a new network request. Clicking on that link will get you that page lickety-split.

Mind you, in the case of The Session, the navigations were already really fast—performance is a feature—so it’s hard to guage how much of a practical difference it makes in this case, but it still seems like a no-brainer to me: taking a few minutes to add this to your site is worth doing.

Oh, there’s one more thing to be aware of when you’re implementing speculation rules. You have the option of excluding URLs from being pre-fetched or pre-rendered. You might need to do this if you’ve got links for adding items to shopping carts, or logging the user out. But my advice would instead be: stop using GET requests for those actions!

Most of the examples given for unsafe speculative loading conditions are textbook cases of when not to use links. Links are for navigating. They’re indempotent. For everthing else, we’ve got forms.

Baseline progressive enhancement

Support for view transitions for regular websites (as opposed to single-page apps) will ship in Chrome 126. As someone who’s a big fan—to put it mildly—I am very happy about this!

Hopefully Firefox and Safari won’t be too far behind. But it’s still worth adding view transitions to your website even if not every browser supports them. They’re the perfect example of a progressive enhancement.

The browsers that don’t yet support view transitions won’t be harmed in any way if you give them the CSS for view transitions. They’ll just ignore it. For users of those browsers, nothing changes.

Then when those browsers do ship support for view transitions, your website automatically gets an upgrade for those users. Code you’ve already written starts working from one day to the next.

Don’t wait, is what I’m saying.

I really like the Baseline initiative as a way to track browser support. It’s great to see it in use on MDN and Can I Use. It’s very handy having a glanceable indication of which browser features are newly available and which are widely available.

But…

Not all browser features work the same way. For features that work as progressive enhancements you don’t need to wait for them to be widely available.

Service workers. Preference queries. View transitions.

If a browser doesn’t support one of those features, that’s fine. Your website won’t break in that browser.

Now that’s not true of all browser features, particularly some JavaScript APIs. If a feature is critical for your site to function then you definitely want to wait until it’s widely supported.

Baseline won’t tell you the difference between those two different kinds of features.

I don’t want Baseline to get too complicated. Like I said, I really like how it’s nice and glanceable right now. But it would be nice if there way some indication that a newly-available feature is a progressive enhancement.

For now it’s up to us to make that distinction. So don’t fall into the trap of thinking that just because a feature isn’t listed as widely-available you can’t use it yet.

Really you want to ask two questions:

  1. How widely available is this feature?
  2. Can this feature be used as a progressive enhancement?

If Baseline tells you that the answer to the first question is “newly-available”, move on to the second question. If the answer to that is “no, it can’t be used as a progressive enhancement”, don’t ship that feature in production just yet.

But if the answer to that second question is “hell yeah, it’s a progressive enhancement!” then go for it, regardless of the answer to the first question.

Y’know, there’s a real irony in a common misunderstanding around progressive enhancement: some people seem to think it’s about not being able to use advanced browser features. In reality it’s the opposite. Progressive enhancement allows you to use advanced browser features even before they’re widely supported.

Displaying HTML web components

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.

button invoketarget=”share”

I’ve written quite a bit about how I’d like to see a declarative version of the Web Share API. My current proposal involves extending the type attribute on the button element to support a value of “share”.

Well, maybe a different attribute will end up accomplishing what I want! Check out the explainer for the “invokers” proposal over on Open UI. The idea is to extend the button element with a few more attributes.

The initial work revolves around declaratively opening and closing a dialog, which is an excellent use case and definitely where the effort should be focused to begin with.

But there’s also investigation underway into how this could be away to provide a declarative way of invoking JavaScript APIs. The initial proposal is already discussing the fullscreen API, and how it might be invoked like this:

button invoketarget="toggleFullsceen"

They’re also looking into a copy-to-clipboard action. It’s not much of a stretch to go from that to:

button invoketarget="share"

Remember, these are APIs that require a user interaction anyway so extending the button element makes a lot of sense.

I’ll be watching this proposal keenly. I’d love to see some of these JavaScript cowpaths paved with a nice smooth coating of declarative goodness.

Lost in calculation

As well as her personal site, wordridden.com, Jessica also has a professional site, lostintranslation.com.

Both have been online for a very long time. Jessica’s professional site pre-dates the Sofia Coppola film of the same name, which explains how she was able to get that domain name.

Thanks to the internet archive, you can see what lostintranslation.com looked like more than twenty years ago. The current iteration of the site still shares some of that original design DNA.

The most recent addition to the site is a collection of images on the front page: the covers of books that Jessica has translated during her illustrious career. It’s quite an impressive spread!

I used a combination of CSS grid and responsive images to keep the site extremely performant. That meant using a combination of the picture element, source elements, srcset attributes, and the sizes attribute.

That last part always feels weird. I have to tell the browser what sizes the images will displayed at, which can change depending on the viewport width. But I’ve already given that information in the CSS! It feels weird to have to repeat that information in the HTML.

It’s not just about the theoretical niceties of DRY: Don’t Repeat Yourself. There’s the very practical knock-on effects of having to update the same information in two places. If I update the CSS, I need to remember to update the HTML too. Those concerns no longer feel all that separate.

But I get it. Browsers use a look-ahead parser to start downloading images as soon as possible, so I understand why I need to explicitly state what size the images will be displayed at. Still, it feels like something that a computer should be calculating, not something for a human to list out by hand.

But wait! Most of the images on that page also have a loading attribute with a value of “lazy”. That tells browsers they don’t have to download the images immediately. That sort of negates the look-ahead parser.

That’s why the HTML spec now includes a value for the sizes attribute of “auto”. It’s only supposed to be used in conjunction with loading="lazy" (otherwise it means 100vw).

Browser makers are on board with this. You can track the implementation progress for Chromium, WebKit, and Firefox.

I would very much like to see this become a reality!

HTML web components

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.

Making the Patterns Day website

I had a lot of fun making the website for Patterns Day.

If you’re interested in the tech stack, here’s what I used:

  1. HTML
  2. CSS

Actually, technically it’s all HTML because the styles are inside a style element rather than a separate style sheet, but you know what I mean. Also, there is technically some JavaScript but all it does is register a service worker that takes care of caching and going offline.

I didn’t use any build tools. There was no pipeline. There is no node_modules folder filling up my hard drive. Nothing was automated. The website was hand-crafted the long hard stupid way.

I started with the content. I wrote out the words and marked them up with the most appropriate HTML elements.

A screenshot of an unstyled web page for Patterns Day.

Time to layer on the presentation.

For the design, I turned to Michelle for help. I gave her a brief, describing the vibe of the conference, and asked her to come up with an appropriate visual language.

Crucially, I asked her not to design a website. Instead I asked her to think about other places where this design language might be used: a poster, social media, anything but a website.

Partly I was doing this for my own benefit. If you give me a pixel-perfect design for a web page and tell me to code it up, either I won’t do it or I won’t enjoy it. I just don’t get any motivation out of that kind of direct one-to-one translation.

But give me guardrails, give me constraints, give me boundary conditions, and off I go!

Michelle was very gracious in dealing with such a finicky client as myself (“Can you try this other direction?”, “Hmm… I think I preferred the first one after all!”) She delivered a colour palette, a type scale, typeface choices, and some wonderful tiling patterns …it is Patterns Day after all!

With just a few extra lines of CSS, the basic typography was in place.

A screenshot of the web page for Patterns Day with web fonts applied.

I started layering on the colours. Even though this was a one-page site, I still made liberal use of custom properties in the CSS. It just feels good to be able to update one value and see the results, well …cascade.

A screenshot of the web page for Patterns Day with colours added.

I had a lot of fun with the tiling background images. SVG was the perfect format for these. And because the tiles were so small in file size, I just inlined them straight into the CSS.

By this point, I felt like I was truly designing in the browser. Adjusting spacing, playing around with layout, and all that squishy stuff. Some of the best results came from happy accidents—the way that certain elements behaved at certain screen sizes would lead me into little experiments that yielded interesting results.

I’m not sure it’s possible to engineer that kind of serendipity in Figma. Figma was the perfect tool for exploring ideas around the visual vocabulary, and for handing over design decisions around colour, typography, and texture. But when it comes to how the content is going to behave on the World Wide Web, nothing beats a browser for fidelity.

A screenshot of the web page for Patterns Day with some changes applied.

By this point I was really sweating the details, like getting the logo just right and adjusting the type scale for different screen sizes. Needless to say, Utopia was a godsend for that.

I was also checking back in with Michelle to get her take on design decisions I was making.

I could’ve kept tinkering but the diminishing returns were a sign that it was time to put this out into the world.

A screenshot of the web page for Patterns Day with the logo in place.

It felt really good to work on a web page like this. It felt like I was getting my hands into the soil of the web. I don’t think it’s an accident that the result turned out to be very performant.

Getting hands-on like this stops me from getting rusty. And honestly, working with CSS these days is a joy. There’s such power to be had from using var() in combination with functions like calc() and clamp(). Layout is a breeze with flexbox and grid. Browser differences are practically non-existent. We’ve never had it so good.

Here’s something I noticed about my relationship to CSS; my brain has finally made the switch to logical properties. Now if I’m looking at some CSS and I see left, right, top, or bottom, it looks like a bug to me. Those directional properties feel loaded with assumptions whereas logical properties feel much more like working with the grain of the web.