Hi there,
In your combobox, place an onChange event that would open up a new window. In the first parameter of open(), make sure to pass whatever has been selected (i.e. selectedIndex.value) via GET. For the destination file, receive the GET parameter and you can do whatever you want with it then.
Something like this, if you insist that you don't know much about JavaScript
:
The above pops up a new window (URL= my.php) with whatever has been selected (its value attribute: e.g. If Option BAR is selected, it will be "bar"). In my.php, you can get this value by referring to $_GET['addr'].
I set the location to be true to see if the parameter is really passed, but you can configure in a way you like. open() is one of the most used, if not the most abused, JavaScript functions and I am sure you can find plenty of info about it and I recommend that you learn.
Good luck.