This is an example of some possibilities of JavaScript. You can read the code of this applet : click on your menu View - Page source (or something like that, depending on your browser).
Describe your function and graph it !
Warnings
All the stuff has been transferred, but computing may take some time, depending on the size of the graph (Width * Height), the complexity of your function, and the performances of your computer (and of your browser)...
No control is made on the evaluation of the function : specify an interval [xmin, xmax] avoiding division by zero and others numerical horrors !
All common expressions should be recognized : cos, sqrt, log, etc. Use * for multiplication and x for the variable, and x * x for x2.
Remarks, bugs reports and improvements are welcome : thierry@thomas.as.