Firedoclipse

Fast full documentation in Eclipse & Firefox.
Works with Java, JavaScript, HTML, & Ant.
Questions?

Point to a keyword in Eclipse.
Alt-click. (configurable)
Read documentation in Firefox.

First, click here to install Firedoclipse in Firefox 3+; then restart.

Now, install Firedoclipse in Eclipse 3.4:
Help → Software Updates → Add Site...
http://people.csail.mit.edu/maxg/uid/firedoclipse