In the last section, we made an explanatory graphic that used interaction to guide the user through the data. Often, however, the goal is just to make a dataset interactive and give the user some way of manipulating it, in other words, an exploratory graphic.

D3's behaviors save a boatload of time setting up the more complex interactions in a chart. Additionally, they're designed to handle differences in input devices, so you only have to implement a behavior once to have it work with both a mouse and touch device. The two currently supported behaviors are drag and zoom, which will get you pretty far.