Sometimes, when the ol' fever comes back and nobody's there to remind me that we have come to accept HTML/CSS, I dream of a world wide web built on TeX and TeX alone. It's a place of wonder, and happiness, and river-less paragraphs. Then I wake up, sweating, screaming, to a world without proper hyphenation. XeTeX is my XaNaX. Makes the web-pain go away.
[MathJax, on the other hand, looks glorious. Many thanks to the people in charge of the project!]
If you're bothered by rivers and lack of hyphenation, check out a project I worked on a while ago, which implements the Knuth and Plass line breaking algorithm in JavaScript. Combined with Hyphenator.js, the results are nearly indistinguishable from TeX output.
Earlier incarnations made it to HN before, but unlike the old version this renders in plain HTML instead of Canvas, so text can be selected, copied, etc.
You probably could get it working, but the implementation isn't (yet) capable of dealing with arbitrary HTML. It only expects paragraphs and images. This is only a matter of implementation though, the core algorithm should be able to deal with most of the content found on websites.
I'm talking to Filipe Fortes of Treesaver about implementing it as part of his Treesaver technology (demo: http://treesaver.publicintegrity.org/smoke_screen) Perhaps a general implementation will roll out of that.
[MathJax, on the other hand, looks glorious. Many thanks to the people in charge of the project!]