content-visibility in Safari

Earlier this year I wrote about some performance improvements to The Session using the content-visibility property in CSS.

If you say content-visibility: auto you’re telling the browser not to bother calculating the layout and paint for an element until it needs to. But you need to combine it with the contain-intrinsic-block-size property so that the browser knows how much space to leave for the element.

I mentioned the browser support:

Right now content-visibility is only supported in Chrome and Edge. But that’s okay. This is a progressive enhancement. Adding this CSS has no detrimental effect on the browsers that don’t understand it (and when they do ship support for it, it’ll just start working).

Well, that’s happened! Safari 18 supports content-visibility. I didn’t have to do a thing and it just started working.

But …I think I’ve discovered a little bug in Safari’s implementation.

(I say I think it’s a bug with the browser because, like Jim, I’ve made the mistake in the past of thinking I had discovered a browser bug when in fact it was something caused by a browser extension. And when I say “in the past”, I mean yesterday.)

So here’s the issue: if you apply content-visibility: auto to an element that contains an SVG, and that SVG contains a text element, then Safari never paints that text to the screen.

To see an example, take a look at the fourth setting of Cooley’s reel on The Session archive. There’s a text element with the word “slide” (actually the text is inside a tspan element inside a text element). On Safari, that text never shows up.

I’m using a link to the archive of The Session I created recently rather than the live site because on the live site I’ve removed the content-visibility declaration for Safari until this bug gets resolved.

I’ve also created a reduced test case on Codepen. The only HTML is the element containing the SVGs. The only CSS—apart from the content-visibility stuff—is just a little declaration to push the content below the viewport so you have to scroll it into view (which is when the bug happens).

I’ve filed a bug report. I know it’s a fairly niche situation, but there are some other issues with Safari’s implementation of content-visibility so it’s possible that they’re all related.

Web Push on iOS - 1 year anniversary - Webventures

Web Push on iOS is nearing its one year anniversary. It’s still mostly useless.

Sad, but true. And here’s why:

On iOS, for a website to be able to ask the user to grant the push notification permission, it needs to be installed to the home screen.

No other browser on any of the other platforms requires you to install a website for it to be able to send push notifications.

Apple is within their rights to withhold Web Push to installed apps. One could argue it’s not even an unreasonable policy - if Apple made installing a web app at least moderately straightforward. As it is, they have buried it and hidden important functionality behind it.

I really, really hope that the Safari team are reading this.

News from WWDC22: WebKit Features in Safari 16 Beta | WebKit

Good news and bad news…

The good news is that web notifications are coming to iOS—my number one wish!

The bad news is that it won’t happen until next year sometime.

The Optional Chaining Operator, “Modern” Browsers, and My Mom - Jim Nielsen’s Blog

This is something I bump against over and over again: so-called evergreen browsers that can’t actually be updated because of operating system limits.

From what I could gather, the version of Chrome was tied to ChromeOS which couldn’t be updated because of the hardware. No new ChromeOS meant no new Chrome which meant stuck at version 76.

But what about the iPad? I discovered that my Mom’s iPad was a 1st generation iPad Air. Apple stopped supporting that device in iOS 12, which means it was stuck with whatever version of Safari last shipped with iOS 12.

So I had two older browsers that couldn’t be updated. It was device obsolescence because you couldn’t install the latest browser.

Websites stop working and the only solution is to buy a whole new device.

Webrise

Prompted by my talk, The State Of The Web, Brian zooms out to get some perspective on how browser power is consolidated.

The web is made of clients and servers. There’s a huge amount of diversity in the server space but there’s very little diversity when it comes to clients because making a browser has become so complex and expensive.

But Brian hopes that this complexity and expense could be distributed amongst a large amount of smaller players.

10 companies agreeing to invest $10k apiece to advance and maintain some area of shared interest is every bit as useful as 1 agreeing to invest $100k generally. In fact, maybe it’s more representative.

We believe that there is a very long tail of increasingly smaller companies who could do something, if only they coordinated to fund it together. The further we stretch this out, the more sources we enable, the more its potential adds up.

the Web at a crossroads - Web Directions

John weighs in on the clashing priorities of browser vendors.

Imagine if the web never got CSS. Never got a way to style content in sophisticated ways. It’s hard to imagine its rise to prominence in the early 2000s. I’d not be alone in arguing a similar lack of access to the sort of features inherent to the mobile experience that WebKit and the folks at Mozilla have expressed concern about would (not might) largely consign the Web to an increasingly marginal role.