WHATWG HTML Standard VS webcomponents

WHAT-WG HTML

There's a long-standing WHATWG feature request open for it here: https://github.com/whatwg/html/issues/2791

And several userland custom element implementation, like https://www.npmjs.com/package//html-include-element

One of the cool things that you can do with client-side includes and shadow DOM is render the included HTML into a shadow root that has s, so that the child content of the include element is slotted into a shell implemented by the included HTML.

This lets you do things like have the main page be the pre-page content and the included HTML be a heavily cached site-wide shell, and then another per-user include with personalized HTML - all cached appropriately.

The `allow` attribute on iframes is a relatively recent API addition from 2017

https://github.com/whatwg/html/pull/3287

I think there's a pretty strong argument at this point for this kind of replacing DOM with a response behavior being part of the platform.

I think the first step would be an element that lets you load external content into the page declaratively. There's a spec issue open for this: https://github.com/whatwg/html/issues/2791

And my custom element implementation of the idea: https://www.npmjs.com/package/html-include-element

Then HTML could support these elements being targets of links.

> Consider https://www.ietf.org/rfc/rfc1866.txt vs https://html.spec.whatwg.org/multipage/

I thought, oh, that's not so bad. Then I realized what I was looking at was a 10 page index.

I'd love to see something like HTMX get standardized, but I'm extremely pessimistic for HTMX's prospects for standardization in HTML.

In talking to a few standards folks about it, they've all said, "oh, yeah, you want declarative AJAX; people have tried and failed to get that standardized for years." Even just trying to get

to target a section of the page that isn't an has been argued about and hashed out for years.<p>Why is that? Well, for example, here's the form you have to fill out to start standardizing a front-end feature. <a href="https://github.com/whatwg/html/issues/new?assignees=&labels=addition%2Fproposal%2Cneeds+implementer+interest&projects=&template=1-new-feature.yml">https://github.com/whatwg/html/issues/new?assignees=&labels=...</a><p>It asks three main questions:<p>* What problem are you trying to solve?

The issue with a single global event handler is discussed here: https://github.com/WICG/close-watcher#a-single-event

If you use popover="", you get the kind of functionality you're discussing for free. For

, the discussion is in progress and reaching a conclusion: https://github.com/whatwg/html/issues/9373

It's not all that shiny. Web components have global names (you should pretty much apply a prefix/namespace if you want to work with others) and managing multiple version of the same component in the same page is an issue in any non trivial codebase (either use a different name per version or fix all breaking changes at once during the upgrade, unless the draft about scoping web elements became standard https://github.com/WICG/webcomponents/blob/gh-pages/proposal... )

I've recently just started playing with Web Components without a build environment. Meaning, no npm, no bun, no webpack, etc, and no dependencies; in typescript. Intellij can autocompile down to js and the browser view injects a small onchange handler for live updates when developing. So far no problems.

The only thing holding web components back seems to be HTML Modules; being able to link to a .html file instead of a .js file to import a web component. Because of this if you want to use templates or anything more complicated you need to do the ugly inject of .innerHtml = `...`, which I thought would be a problem but the IDE parses the template string very nicely. It would be great to make a component in HTML and any javascript you would put in a tag. It seems like there a lot of bureaucracy involved in getting HTML Modules out the door since its been eight years.<p><a href="https://github.com/WICG/webcomponents/blob/gh-pages/proposals/html-modules-explainer.md#high-level-summary">https://github.com/WICG/webcomponents/blob/gh-pages/proposal...</a>

We're trying to advocate for greater flexibility in cross-component styling. One proposal is "open styleable shadow-roots" which would be an opt-in to let styles from above a component to apply to it's shadow root. I think this would help migration in situations where app teams are currently using global stylesheets.

Feedback and support of the need for something like this would help a lot: https://github.com/WICG/webcomponents/issues/909

))

Part 1.

> I honestly believe that 90% of the dislike for WC comes from the name "connectedCallback". If they'd named it "onCreate" or something, everyone would be using it

Of course not. None of the criticism towards Web Components ever mentions "connectedCallback", or how it should be named differently.

Do you know the actual reason so few are using them? Let's skip the atrocious not-really-high-level not-really-low-level imperative API that they offer.

How about:

- 13 years after introduction they still need 20 more specs to try and patch just some of the holes in their original design: https://w3c.github.io/webcomponents-cg/2022.html

- Shadow DOM is infecting every spec so that the actual useful specs like Scoped CSS have to be delayed almost indefinitely to try and figure out how to work with this abomination of a design

To quote the report linked above, "many of these pain points are directly related to Shadow DOM's encapsulation"

- The amount of specs that are required to make them work, barely, and be "good web citizens". And the amount of APIs.

Oh, you want your custom input to a) be able to send its data in a form, and b) be accessible to a label outside of your component? Well, there's a separate API for a) and there's some separate future API for b). And meanwhile your custom button won't be able to submit your form, sorry, it's a 4-year old issue with no solution: https://github.com/WICG/webcomponents/issues/814

And all that despite the fact that there are already a dozen specs covering web components, and dozens more on their way.

- Web Components ar HTMLElement. It means you cannot use them inside SVGs.

This is impossible:

The lit-plugin in for VS Code offers syntax highlighting, jumpt-to-definition, etc: https://marketplace.visualstudio.com/items?itemName=runem.li...

Prettier already supports HTML in html`` strings, likewise, CSS.

> Is there a way in Lit to write the templates in regular HTML rather than a string?

This would require a compiler. You would need to load the HTML into the JS module graph and JS can't do that yet, though there is a proposal for it: https://github.com/WICG/webcomponents/blob/gh-pages/proposal...

Template in HTML also have the problem of the data not being in scope as it is in JS, and there not being an expression language. So you ned up having to re-implement a lot of JS embedded into the HTML syntax, which then preferences a compiler-based approach to make fast. It turns out to be a lot simpler to embed HTML in JS.

It's more than just sugar now. You can't even write web components functionally: https://github.com/WICG/webcomponents/issues/587

gzip/brotli handles this very well, but it still is text to parse through.

Some form of declarative CSS module scripts would help a lot. A feature request for that here: https://github.com/WICG/webcomponents/issues/939

In the past I've seen this one:

https://github.com/WICG/webcomponents/blob/gh-pages/proposal...

Perhaps there are more recent versions.

I liked the spirit of the proposal, but never studied it.