A jQuery plotting and chart plugin.
The tool allows you to create line, bar and pie charts, with features that reach beyond typical chart functionality, like zoom proxies, dynamic replotting, Mekko charts, trend lines, block plots, log axes, and more. All of these plot elements are handled by pluggable renders, which allow them to be customized to each user's needs.
To help you get started the project's website offers an extensive library of step-by-step examples.
Image: A screenshot of the jqPlot Mekko Charts example page.
jqPlot is currently compatible with IE 7, IE 8, Firefox, Safari, and Opera.