Javascript libraries for drawing multilevel trees

I would like to know about the available js libraries for drawing multilevel trees. Some functionalities I'd like to add to the created tree would be to make the nodes click-able and to be able to select an are开发者_JS百科a on the graph and do actions based on the selection.

Maybe you should try arbor.js?

I'd check out Protovis. I've had good success with it. However, it is a very general library, giving you lots of building blocks to make nice graphs, but it won't be a turnkey solution.