could you please provide the sample Html file to traige the issue further.


Thanks.

http://codepen.io/edoardocavazza/pen/NREZQm?editors=1111

The examples provided by "edo" are not conform to current V1 specification.

First of all, it looks like the implementation is not complete:
https://bugs.chromium.org/p/chromium/issues/detail?id=652579

Secondly, the example should rather bethe following:

  1. class MyDiv extends HTMLDivElement {}
  2. customElements.define('my-div', MyDiv, { extends: 'div' })
  3. document.createElement('div', {is: 'my-div'})
  4. new MyDiv()

TL;DR the example uses V0 API instead of V1, but even using proper V1 API nothing works as expected.

Best Regards

yurak is working on this. Assigning to me because she doesn't have editbugs yet IIRC.

What you're seeing here results from customized built-in elements not being implemented in customElements.define, but createElement('foo', 'x-bar') creates an element for the old document.register custom elements.

By the way, document.createElement('div', 'my-div') is a very old draft of the custom elements spec that only Chrome implements. The new syntax is document.createElement('div', {is: 'my-div'}). That doesn't work yet, but when it does, we plan to deprecate and remove the createElement(string, string) version so be ready for that!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fe200cd217b99368dbded68a0350d33c552c6a5b

commit fe200cd217b99368dbded68a0350d33c552c6a5b
Author: yurak <yurak@google.com>
Date: Fri Nov 18 08:08:40 2016

https://dom.spec.whatwg.org/#dom-document-createelement
    Definition is checked for HTML namespace elements in document.createElement
    Customized built-in elements can now be created with the document.createElement
        NOTE: This is behind runtime enabled flag "CustomElementsBuiltin".

Syntax:
    https://html.spec.whatwg.org/multipage/scripting.html#custom-elements-customized-builtin-example

Implemented create element algorithm
    https://dom.spec.whatwg.org/#concept-create-element
Steps 5-7:
    /core/dom/custom/CustomElement.cpp

Added some tests.

(Sorry this patch is big)

BUG= 648828 , 657583 

Review-Url: https://codereview.chromium.org/2477713003
Cr-Commit-Position: refs/heads/master@{#433146}

[modify] https://crrev.com/fe200cd217b99368dbded68a0350d33c552c6a5b/third_party/WebKit/LayoutTests/custom-elements/spec/create-element-defined-synchronous.html
[add] https://crrev.com/fe200cd217b99368dbded68a0350d33c552c6a5b/third_party/WebKit/LayoutTests/custom-elements/spec/create-element.html
[modify] https://crrev.com/fe200cd217b99368dbded68a0350d33c552c6a5b/third_party/WebKit/LayoutTests/custom-elements/v0-v1-interop.html
[delete] https://crrev.com/bd0d9c52947c4db46e946743783660bd06354359/third_party/WebKit/LayoutTests/fast/dom/custom/create-element-second-arg.html
[modify] https://crrev.com/fe200cd217b99368dbded68a0350d33c552c6a5b/third_party/WebKit/Source/core/dom/Document.cpp
[modify] https://crrev.com/fe200cd217b99368dbded68a0350d33c552c6a5b/third_party/WebKit/Source/core/dom/custom/CustomElement.cpp
[modify] https://crrev.com/fe200cd217b99368dbded68a0350d33c552c6a5b/third_party/WebKit/Source/core/dom/custom/CustomElement.h

The assigned owner "yurak@google.com" is not able to receive e-mails, please re-triage.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

I believe yurak's patch fixed this, provided you use the new APIs and enable the feature flag.