MathJax is an open-source JavaScript display engine for LaTeX, MathML, and AsciiMath notation that works in all modern browsers. It was designed with the goal of consolidating the recent advances in web technologies into a single, definitive, math-on-the-web platform supporting the major browsers and operating systems, including those on mobile devices. It requires no setup on the part of the user (no plugins to download or software to install), so the page author can write web documents that include mathematics and be confident that users will be able to view it naturally and easily. One simply includes MathJax and some mathematics in a web page, and MathJax does the rest.
MathJax uses web-based fonts (in those browsers that support it) to produce high-quality typesetting that scales and prints at full resolution (unlike mathematics included as images). MathJax can be used with screen readers, providing accessibility for the visually impaired. With MathJax, mathematics is text-based rather than image-based, and so it is available for search engines, meaning that your equations can be searchable, just like the text of your pages. MathJax allows page authors to write formulas using TeX and LaTeX notation, MathML, a World Wide Web Consortium standard for representing mathematics in XML format, or AsciiMath notation. MathJax will even convert TeX notation into MathML, so that it can be rendered more quickly by those browsers that support MathML natively, or so that you can copy and paste it into other programs.
MathJax is modular, so it loads components only when necessary, and can be extended to include new capabilities as needed. MathJax is highly configurable, allowing authors to customize it for the special requirements of their web sites. Finally, MathJax has a rich application programming interface (API) that can be used to make the mathematics on your web pages interactive and dynamic.