Provides browsing capability to the PDB web site.

The only way we can display large trees (e.g. Taxonomy with 100K+ nodes) in a web application is to only serve the client the nodes needed for the immediate display, plus the children of displayed nodes. When a user clicks on a node the children are displayed immediately, then a hidden frame requests new nodes from the server and Javascript code is returned to the hidden frame that populates a Javascript tree widget with more nodes along the path indicated by the clicked node. So, with that explanation out of the way, I can get into the details of exactly what we tried and what we use.

We tried many commercial and open-source Javascipt tree widgets (the best was from www.blueshoes.org) but all were too slow, so I wrote a tree widget that was quick enough from scratch. The only reason it can be quicker than the other trees is that it only performs the operations we need for our tree display, without any of the features that the normal tree widgets have. For a while we used the morten javascript tree, but it requires frames and couldn't be used when we went to a frameless site. I'll be glad to send you any of the code you need/want (the Java server-side code, or the Javascript web-client code).