This is a nifty visualisation by Hui Jing. It’s really handy to have elements categorised like this:
This really gets to the heart of one of the biggest benefits of HTML web components: composability. You can nest your regular markup inside multiple custom elements; something that is can’t do.
The other exciting approach doesn’t exist yet: custom attributes. Again, they’d be a great way of using composability to turbo-charge your existing HTML in all sorts of ways.
Web development follows a familiar cycle. First we glue together a solution with whatever we have — JavaScript, image hacks, Flash, anything. Then the platform matures, and CSS or HTML eventually makes that same workaround native. Rounded corners, custom fonts, smooth scrolling, sticky positioning: all of these started as JavaScript-heavy hacks before CSS turned them into a single declaration.
We are in another one of those transition moments. A new wave of long-requested CSS features is finally landing, and many of them are explicitly designed to replace patterns that used to require JavaScript. Not as approximations — as first-class platform primitives that handle the edge cases, run in the right thread, and need zero dependencies.
I’m slapping my forehead—progressive web components is a perfect name for what I’ve been calling HTML web components. Why didn’t I think of that?
A Progressive Web Component is a native Custom Element designed in two layers: a base layer of HTML and CSS that renders immediately, without JavaScript, and an enhancement layer of JavaScript that adds reactivity, event handling, and more advanced templating.
This is a clever technique for a CSS/HTML only way of just-in-time loading of iframes using details and summary.
This is an excellent one-stop shop of interface patterns:
This is an organic collection of common JS patterns that can be replaced with just HTML, CSS, and no, or very low, JS. As HTML and CSS continue to mature, this collection should expand.
Here’s an HTML web component you can use if you’re participating in the origin trial for the Web Install API.
Have you got the perfect talk for this event? Let me know!
A one-day event all about what you can in web browsers today: Brighton, March 12th, 2026. Tickets are just £225+VAT!
Some handy tips courtesy of Chris Ferdinandi.
Turning accessibility awareness into action with HTML.