MathJax grew out of the popular jsMath project, an earlier Ajax-based math rendering system developed by Davide Cervone in 2004. In the following years, there were many significant developments relevant for web publication of mathematics: consolidation of browser support for CSS 2.1, Web Font technology, adoption of math accessibility standards, and increasing usage of XML workflows for scientific publication.
In 2009, AMS, Design Science, and SIAM formed the MathJax Consortium to enable Cervone and others to design MathJax from the ground up as a next-generation platform, while still benefiting from the extensive real-world experience gained from jsMath. Since its initial release in 2010, MathJax has become the gold standard for mathematics on the web.
Today MathJax is a project of the MathJax Consortium, a joint venture of the American Mathematical Society (AMS) and the Society for Industrial and Applied Mathematics (SIAM) to advance mathematical and scientific content on the web.
More information and download at http://www.mathjax.org/