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Please remind us again why this needs to be a processing instruction? Basically it’s declarative shadow dom without the shadow dom, right?

It's one of the only way to make these things not interfere with the DOM, eg if you want to replace table rows.

github.comUpcoming WHATNOT meeting on 2026-01-08 · Issue #12034 · whatwg/htmlWhat is the issue with the HTML Standard? Today we held our weekly triage call (#12015) and the meeting notes are posted there. The next one is scheduled for January 8th, 2026, at 9AM PDT. Note tha...

This originally started using actual HTML elements as you can see in the history of the explainer. This was discussed extensively as part of standardisation. E.g. github.com/whatwg/html/... PIs offer many benefits, including being able to slot in sections without altering the DOM with a container.

Danny Engelman 🌷🏍️🛥️

@engelman.nl

I have chosen, many moons ago, to only use technologies supported by all 3 browser vendors Done my tour of duty in Mosaic, Netscape days Got the scars from pre-jQuery days I read the .dev post, looks interesting, but technology only works when y'all co-operate, not just because something is cool.

So far a (pending) official positive standards position from Mozilla and WebKit, and close collaboration on the details of this over the last year or so.

Oh there’s been a lot of cooperation on these and we’ve got a lot of feedback and positive signals from other browser vendors. There are PRs open to add them to the relative specs (HTML and the like) and we expect those to land soon. At which point we’ll ship it unflagged!

@nicolesullivan.bsky.social

No ETA on when it will actually land in other browsers though, but someone has to go first and we’re happy to take that on. The important thing is we have good consensus on these (that doesn’t always happen, but we try!). And in the meantime we’ve released some polyfills to help with that.

Nicole Sullivan

@react.dev/facebook told our team years ago that they’d only use this kind of thing if they could synchronize updates so it wasn’t like “popcorn” randomly popping into the page. Does The API support that? Templates can be small like items in a list. Did you picture the API being used on page load?

Not supported at the moment but it has been brought up (not by react folks specifically) together with other requested future enhancements. See github.com/WICG/declara... for current thinking on this.

Yeah this would be incredible! If you want a super simple way to try it out I built a jsx framework for streaming HTML. You can just use generator fns to yield the marker, await some task, then stream in the rest without client js. ovrjs.com

amaze amaze amaze!

Cool, article, one point of clarification: > A common pattern popularized by frameworks like Astro and React is the island architecture where components are hydrated independently on top of static HTML. React never implemented islands and were explicitly against the idea.

EINS78

@eins78.com

to be fair, it was always very easy to implement "islands" yourself with React. the whole concept of "hydration" did not exist before in any framework – that's what initially drew me to it. remember "isomorphic" components? 😅

Fair. Will correct. I more meant that React helped popularize component-based architecture, but agree that was different to islands.

Matthew Phillips

@handle.invalid

Definitely not asking you to update the article! I'm just being pedantic.

In the middle of fixing another couple of things anyway! So it's no bother.

Matthew Phillips

@handle.invalid

Credit goes to Katie Sylor-Miller for coming up with the idea, Jason for writing the article that inspired a lot of people, and Astro for implementing a popular framework around it.

Yup big fans of @ksylor.bsky.social @developit.dev and all the @astro.build folks!

Datastar Cult Leader

@data-star.dev

data-star.devDatastarThe hypermedia framework.

We've been doing this real-time in user land for years. Please check out data-star.dev and the SDK ADRs. Reach out if you have questions!

Anthony Frehner

@frehner.me

Dumb questions that I can’t remember the answers to: 1. Can the template contain JS that will execute upon insertion? 2. Can the template be in the DOM before the referenced PI is? Very nice though! Been watching this for a while!

1. Yes 2. I think no but can you rephrase the question or give an example? I might not get the q

Anthony Frehner

@frehner.me

Put another way: is the order that the PI must always come first and then the template? Or (for whatever reason) can the template come first and then the PI?