protovis part 4: external data and animated labels

Open the bar chart file and in the head area, lets add a new script that loads an external data file. Notice the source URL doesn't have any http information. That's because we're going to use a relative link. This means that as long as the data file is in the same folder as the html file you're working on, Protovis will be able to use it.

We also need to set the type to text/javascript. We'll examine the data file more closely in a moment, but first lets do a little set up on our document.