Built-in elements don't work in Firefox about document-register-element

[WebReflection]

So, v1.13.0 is out, and I've also added a how to migrate to V1 with hopefully all the details in (already spotted few typos though, on it already)

[WebReflection]

I still need to support IE11

IE doesn't have customElements so that script tag on top of any of your page would work for IE11 (and many others).

If I remove document-register-element, it works in Firefox too.

That means you shouldn't use DRE in the first place.

I'll try to have a look what is wrong or how I can improve but it seems like you are giving DRE to browsers that shouldn't need it.

Anyway, worth investigating.

[WebReflection]

Are there any plans to remove support for Custom Elements V0 from this polyfill, considering that browsers are already dropping it?

No, but you shouldn't care. V0 is battle tested and used to bring built ins to V1 capable browsers.

Firefox has also been tested extensively, so unless you tell me which version you are using, it's hard for me to do anything here.

The outerHTML trick you mentioned is used in built-in-element which patches only built-in extends for non capable browsers: https://github.com/WebReflection/built-in-element

If you want to use V1 built-in elements, I strongly suggest you use that polyfill instead.

The way you'd go for it is described in the Medium post, summarized as:

<script>
if (!this.customElements)
  document.write('<script src="//unpkg.com/document-register-element"><\x2fscript>');
</script>

You can test the live page there: https://webreflection.github.io/built-in-element/test/es5/

[gkubisa]

Sorry, I should have mentioned the version... it's Firefox 63.0 (64-bit) on Ubuntu 16.04.

I still need to support IE11, so I believe https://github.com/WebReflection/built-in-element would not be enough and I have to use https://github.com/WebReflection/document-register-element.

[gkubisa]

I've just created this jsfiddle to demonstrate the problem: https://jsfiddle.net/0dm72zv6/4/. It works fine in Chrome but fails in Firefox 63. If I remove document-register-element, it works in Firefox too.

[gkubisa]

Ah, that makes sense. Thanks!

Still, I believe that loading document-register-element should be safe in any browser, even if it is not needed.