OK Everybody, lets create a button!
Great!, That was easy.
Now, let's make it difficult.
Setting tabIndex on the Canvas element containing only one element in the subtree.
Sub-tree focus
Implementations which support the Canvas sub-tree appropriately do not need tabIndex on form elements.
Using onclick with button elements works for both mouse and keyboard activation.
Events can be forwarded through simple DOM techniques. Future Canvas implementations may allow authors to bind regions to sub-tree elements.
Keyboard events may be monitored when a Canvas element is in focus and has complex behavior, such as Canvas elements that have multiple controls.
Update the pixel resolution for crisp rendering when desktop zoom is used.
Semantic content such as text displayed to the user should be available in the DOM. The DOM may also provide other userful information, such as user preferences for font size.
Users may choose to access the document through caret browsing and other keyboard techniques. Content selection and editing should be considered during development.
This builds on the programmatically accessible content section.
Define spatial regions on your Canvas in terms of paths, bounding boxes and bind them to underlying elements.