Using variables in url

I have created a php storing values in a mysql database.  I animate I call this php using window.open:

window.open("http://localhost/send_and_update.php?Tid=26&dBA=78 ", "_self");

This works fine, the dataset 26 78 is saved in the database.  But now I want to send values from variables in  i animate.  I try this:

Var time=22

window.open("http://localhost/send_and_update.php?Tid=time&dBA=78 ", "_self");

This won't work.  Any suggestion?

Svein-Tore