Component Model in WebKit

The component model effort brings encapsulation to the Web. See ​use cases for more background.

Implementation Status

_{If this is older than 30 days, it's probably out of date.}

Use ​XBL2 spec as a reference:

Area	Status	Comments
HTML Elements and DOM interfaces	Not yet implemented	Waiting on the plumbing to settle down
pseudo attribute	Same as ​XBL2 pseudo	Allows arbitrary value and CSS machinery has been modified to allow any value
Component lifecycle	Not yet implemented	Native controls implementation uses direct wiring
Shadow DOM	Basic plumbing in place	Instead of it being a <template> element clone, we use a different node type (SHADOW_ROOT_NODE = 14) for the root node
Tree Scopes	Implemented, matches the ​shadow scope notion of in XBL2
Inheritance	Won't be implementing	We decided that this feature is overly complex and unnecessary for the component model. See ​this post to public-webapps
<content> element	Basic building blocks are being used by <summary> and <details>	Need to better understand requirements and use cases to spec/implement properly. Certainly won't be implementing the way it's ​defined in XBL 2.0
CSS matching	Some of the ​selectors and shadow scopes implemented	Need to further align with the XBL2 spec
Events	Matches logic in ​event handlers section	We don't create a separate Event object for each re-targeting, because we don't worry about component isolation (yet)