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Custom Elements

Custom elements is a feature that, until recently, was developed as monkeypatches onto various specifications. To help implementers have a consolidated view of how custom elements change the DOM Standard, we have a few resources.

First, there is a rendered HTML diff containing all the changes related to custom elements.

Second, we provide this listing of affected sections:

• Mutation algorithms: in particular insert and remove
• The clone algorithm, to handle elements specifically
• Interface Document: the createElement and createElementNS IDL definitions and algorithms, and the addition of the ElementCreationOptions dictionary.
• Interface Element:
  • The "custom element state" concept and related definitions
  • The "create an element" algorithm
  • Modifications to changing, appending, removing, and replacing attributes.
  • The attachShadow() method has a provision for custom elements
• Interface DOMImplementation:
  • The createHTMLDocument() method uses "create an element"
• All throughout the spec: [CEReactions] extended attributes are now present

Finally, here is a listing of all relevant commits:

• https://github.com/whatwg/dom/commit/7f63535da39a1cbf7f8f68563abc6f05f760990a
• https://github.com/whatwg/dom/commit/2168da2d46249ce4f03c8d706d1748e54456db17
• https://github.com/whatwg/dom/commit/01145a5b2ca7df2fbf36082f799e5de4da80f4fe
• https://github.com/whatwg/dom/commit/b8d2854152aaabc412063c67bcb4177d8a2607a1
• https://github.com/whatwg/dom/commit/3536dd95dbc6bad216f414d34de6c6805db67e6f
• https://github.com/whatwg/dom/commit/5fc5624fb80648de46088cac06864b4048c1981c
• https://github.com/whatwg/dom/commit/7b42a54ee5876a1767d0a6007f2b9dc32b0034e3
• https://github.com/whatwg/dom/commit/3cd02d139c159a31fbb400e03932652c72fc7812