How to create a multiple linked & directed graph with javascript?

This is my problem: For a school project we are trying to create a directed graph and make it fit in a typical html website. We figured out it had to be written in javascript, because a java applet isn´t an option. So this is开发者_运维百科 how it should look like: image.

The data visualised in the graph will be gathered from some xml files. We took a look at flare and some other packages, but real thing is making a two-way link between the nodes (where the thickness of the arrow represents importance) in our graph. Making the whole thing moveable is also required. Any ideas? Thank you.

Have a look at jsPlumb - a not featurerich but easy customizable jQuery Plugin for directed graphs

http://morrisonpitt.com/jsPlumb/html/jquery/demo.html