onChange event on a combo control

Hi,
Is there any kind of way to attach an ‘onChange’ event to a Combo Control?
The thing I want to achive is to do some ajax calls to a server to fetch some data based upon the value of the combo control.
Thanks, Toon

Then you are selecting some item in combo list - onChange event occurs.

$$(‘combo’).attachEvent(“onChange”, function(newvalue, oldvalue){

});