That isn't well formed, you're missing two </src>.

I dislike XML, the confusion between attributes and sub elements is one of the worst bits.

"1024 large-image.jpg 512 small-image.jpg image.jpg fallback My Image"

That is what your code would look like to browsers that didn't know about the new elements. HTML is defined such that browsers can ignore unknown elements for compatibility and still display the text. Using contents for the metadata means that browsers need to know about the elements to at least hide the text.

Holy crap that's verbose.

This is why *ML is a stupid-ass way to do things. "the problem it solves is not hard, and it does not solve the problem well."

"Attributes are stupid" is also Maven's approach, but this results in unnecessarily verbose XML files.

<imgset w1024="large.jpg" w640="medium.jpg" />

not practical since you'd have to define attributes for every conceivable size in the spec and that's just asking for trouble. e.g. w2048, h1024, w320, w240,h320, wPleaseShootMe :)

But now it's a PITA properly handle and escape for any toolset that don't have good xml support. Imagine people starting to put <![CDATA[ ]] blocks into this.

I meant if I had designed it from the start. Then everything is a tag, no attributes, no quotes, equal signs, etc.

How about JsonML; i.e. XHTML but in JSON format to make it less verbose / further improve integration with javascript?

JsonML is pretty efficient when auto-generated from HTML source. I use it as an intermediate form for client side templates ( http://duelengine.org ) but I don't write it by hand. Its regularity makes it a perfect candidate for output from a parser/compiler.

You'd want to kill yourself pretty quickly.

JSON is great as an interchange format, but there are many reasons editing it by hand is painful, lack of comments and lack of newlines in strings not being the least of them.

There's no syntactic difference between an attribute, an object and an array.

you can't nest tags into attributes

I really dislike your approach.