High-Quality Display

A key requirement for MathJax is that it produce high-quality rendering in all major browsers. Fortunately, the last several years have seen a strong convergence on the part of browser vendors around a collection of standards and technologies sometimes called the Ajax or Web 2.0 platform. That platform includes HTML, CSS 2.1, and JavaScript, and is powerful enough to do high-quality math rendering. It is supported by all current major browsers under Windows, Linux and MacOS. MathJax is being developed and tested against over 20 browsers, including several versions of Internet Explorer, Firefox, Opera, Safari, and Chrome.

The basic idea is that MathJax JavaScript code runs when a page loads, and converts the equation markup embedded in the HTML into CSS markup to position individual characters and symbols according to the principles of mathematics typography. Because the browser is ultimately displaying HTML, equations scale along with the rest of the page, and appear at the same resolution both on screen and in print.

Proper display of symbols is one of the greatest challenges. Mathematics uses a huge variety of symbols and characters, so it is uncommon for a typical reader’s computer system to have fonts containing all of them installed. MathJax employs a three-fold stategy to address this font problem. First, a promising new extension to CSS, often called Web Fonts, allows publishers to install the required fonts on the web server. Browsers can download and utilize them in rendering specific pages, but they are not permanently installed on the client system, so that intellectual property rights in the fonts are protected. Web Fonts are an excellent solution, but they are only implemented in some browsers today. Consequently, MathJax also contains extensive logic for analyzing the fonts available on the client system, and uses those if possible. Finally, if no acceptable fonts can be located on the client system, MathJax uses images of the required symbols. The MathJax distribution will include images of a large collection of symbols and characters at a variety of sizes and resolutions. These images are installed on the server, and used as necessary by MathJax.