We have acquired our toolbox and reviewed the basics of SVG. It is now time to explore D3.js. D3 is the evolution of the Protovis (http://mbostock.github.io/protovis/) library. If you delved into data visualization or were interested in making charts for your web application, you might have used this library. Additional libraries existed that could be differentiated by how fast they rendered graphics and their compatibility with different browsers. For example, Internet Explorer did not support SVG but used its own implementation, VML. This made the Raphaël library an excellent option because Raphaël automatically mapped to either VML or SVG. On the other hand, the easiness of jqPlot and its simplistic jQuery plugin interface allowed developers to adopt it very quickly.

However, Protovis had something different. Given the vector nature of the library, it allowed you to illustrate different kinds of...