I am trying to use a showmodaldialog() popup window. This window has a dropdown which the user will select a set. The particular set which is chosen is supposed to affect what appears in another dropdown right below it.

What I have done in the past with normal windows is just use javascript onChange to reload the window and pass a variable to itself using location.href = 'blah.php?id=+form.set.options[form.set.selectedIndex].value. But, whenever I use location.href on this type of window, I get a new window.

Idea?

BTW, this is using PHP, too, to access data from a database. So, what the user chooses in the first dropdown should trigger a query done by PHP, which should output the options into the second dropdown.

Help would be highly appreciated.