The 'session' state could be implemented in a CGI-way. Give all branches an ID, and give them to states: expanded (0) or collapsed (1). This way, you can address 32 branches in a long integer. So for every 32 branches you assign one number. You can pack/unpack these numbers to a CGI-compatible string with CGIpack. This allows the branches to be coded in a compact url.

In the script, you unpack the url to a series of numbers, which are translated with unpack to a series of bits. With substr you pick the bit for the particular branch, to expand or collapse.

Jeroen
"We are not alone"(FZ)