Jquery-mathml is a project mainly written in JavaScript, it's free.
Superset of jQuery for working with MathML
jquery-mathml.js contains a patched version of jquery 1.4.4 to allow MathML objects to be modified more fluidly. This is very much a proof of concept work.
MathML is only supported by Gecko ( Firefox ) and Opera based browsers at the moment. Internet Explorer and WebKit browsers partially support MathML but their coverage is extremely poor.
See: http://trac.webkit.org/wiki/MathML%20Status
DEMO FOR FIREFOX 3.6+:
Firefox 4 beta is lightyears ahead of other browsers in terms of MathML support, for example if you install the STIX fonts and take a look at the following page you'll find it's nearly identical to LaTeX.
Dual MIT & GPL ... i.e. do whatever you want just include the jQuery authors and my name in any forks.
Stephen Diehl ([email protected])