A Popup for Shopping Cart

A Popup for Shopping Cart

I am not sure if this is the correct forum category or not. If not, my apologies. Please move to the appropriate forum.
 
I am using ProductCart shopping cart for all my ecommerce sites and I wanted to know if there is jquery plugin or script that will allow me to open/close a popup displaying the cart totals.
 
I am looking for something of this nature: http://www.sitepoint.com/examples/ppopup/tooltip4.html
 
I am not fond of the body onload method but the real issue is that the shopping cart totals is dynamically generated and so the info must be updated when a user adds/removes items to the cart regardless if the popup is open or not. Ideally, when the visitor clicks on the shopping cart to view the totals I would like it to stay open even when they add/remove new items to it.
 
The only thing I've found on jquery is this: http://plugins.jquery.com/project/jqWindowsEngine  but I do not know if it will work with a ASP shopping cart. The method they used here is where it calls on a .html file to display in the popup. Again, the cart will need to be able to be updated when a popup is used and I just don't know if this will work.
 
Any suggestions would be helpful.
 
Thanks.