Question : Need to use a jquery modal window to add a var into a session variable upon form submission

I was planning to use this:  http://jqueryui.com/demos/dialog/#modal-form
to create the form but I want the input to go to from the form submission to be saved in a session var.  I will do that via php but need to know how to get the submission to go to a php mod.

Answer : Need to use a jquery modal window to add a var into a session variable upon form submission

You could use Ajax for this. Check this example with login form:

http://www.bitrepository.com/ajax-login-modal-box.html