We don't know of any widely available browsers that support HTML 3.1 Most support all or part of HTML 3.0. Other browsers, like Cello and Microsoft's browser will not display any mathematics at all. Only a few browsers support integrals. Browsers that implement HTML 3.1 should show an integral sign here. Even so, it is fairly easy to read the HTML mark-up and guess what was intended.
Fractions are another matter.
Almost all browsers can show GIF images inline. As a result one can show mathematical formulas by linking to GIF images of the formula. This is the default method for showing formulae used in the Online Exercises system. There's another possibility for displaying mathematics, and that's to use a JAVA applet such as HotEqn , EqnViewer or WebEQ . Another Applet to try You can try the Function Evaluator Applet which is a simle example of an interactive java applet.