heatmap.js | Dynamic Heatmaps for the Web

This JavaScript library will help you make your 3 dimensional data speak up. Use heatmap.js v2.0 to add new value to your project, build a business based on it, study and visualize user behaviour, and much more. Whether you want to have an aggregated overview of your users behaviour, or look at thousands of events distributed on a map… heatmap.js has all your heatmap visualization needs covered!
http://www.patrick-wied.at/static/heatmapjs/