Parsing specified for future updates
Contents
Problem statement / use cases
We must specify the parsing algorithm for HTML5 to facilitate the easiest adoption of new elements in the future.
- UAs do not generally make use of DTD or other parsing definitions so parsing is coded into the UA
- Different UAs handle unknown (or new) elements in different non-interoperable ways
- Parsing unknown elements as block elements prevents the introduction to legacy UAs of new inline elements (instead invoking implied P element clost tags)
- Parsing unknown elements as void elements prevents the introduction to legacy UAs of new non-void elements
- Parsing which moves unknown elements to the body from the head or from the head to the body prevents the introduction of new elements
- The lack of a shortcut mechanism to signal void elements requires the cumbersome use of close tags for newly introduced void elements for legacy UA processing
Proposed solutions
Ensure the parsing algorithm for HTML5:
- processes unknown elements in place (remaining in the head or the body wherever the author includes them)
- treats unknown elements as inline elements so as to not force a implicit P close tag when encountered
- allows authors to use the “/” for self-closing void elements, newly introduced void elements and hence any unknown elements with a self-closing tag should be treated as closed for purposes of tree construction
- adds an "in span" insertion mode where implicit P (paragraph) element close tags are not generated (except for another immediate child P element opening tag).
- adds a "b" boolean attribute to the P element to allow inline-block content (blockquotes, tables and lists)
Discussion and evaluation
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