MathML is an application of XML (Extensible Markup Language) designed to facilitate the use of mathematical expressions in Web pages. Historically, mathematical content has been difficult to portray because standard typographic character sets do not provide for them and because they sometimes exceed a line width in size.
On Web sites, GIF or JPG images must usually be created to portray all but the simplest mathematical expressions. This works, but it does not always look professional, and when the HTML files are saved and then viewed offline, the images do not show up unless they have been individually downloaded and their tags have been made consistent with the offline file. MathML allows the insertion of mathematical expressions within an HTML file as special data. The browser (which must support MathML) can then display the appropriate symbol or expression.
For mathematicians, engineers, and scientists familiar with TeX or LaTeX, MathML can be thought of in this way: It is to HTML as TeX or LaTeX is to plain text. In fact, conversion programs are available that can be used to generate MathML documents from TeX or LaTeX documents.
MathML is in the developmental stages. The ultimate goal is to render mathematical documents directly viewable in, and printable from, popular Web browsers such as Netscape or Microsoft Internet Explorer. Until that ideal is realized, the viewing of mathematical content in Web sites generally requires specialized plug-ins.