One extension to HTML that I think would be very usefule would be a
generalisation of the <img src="URL"> markup. Ideally I would like a markup
which would allow the inclusion of any file type e.g. <include src="URL">.
Instead of adding a new mark-up, why not just extend <A> by adding a parameter
which declares whether the link is included?
<A href="URL" ACCESS="inline">
This will allow extensions for conditional incline inclusion and other kinds
of inline document relationships as necessary.
ACCESS= "jump" - the default go to document.
"inline" - inline the contents of URL.
"toggle" - contents can be opend and closed inline.
"when#var" - inline document when var is true.
This extension could allow specialized mark-up for images to be folded into
<A>, thus reducing the working set and maintaining tight abstraction.