OnChange and DropDownList's - event not being dispatched

Question

I can't get an onChange event to fire when making a ListItem selection in a DropDownList control. Am I doing something wrong? (I'm running XP Pro 32bit)
     var dlg = new Window('dialog');
     var pnl = dlg.add('panel');
     var myDDList1 = pnl.add('dropdownlist',undefined,['one', 'two', 'three'], {name: 'ddList1'});
     myDDList1.addEventListener('change', myFunction);
     var myDDList2 = pnl.add('dropdownlist',undefined,['one', 'two', 'three'], {name:'ddList2'});
     myDDList2.addEventListener('change', myFunction);
     var myDDList3 = pnl.add('dropdownlist',undefined,['one', 'two', 'three'], {name:'ddList3'});
     myDDList3.addEventListener('change', myFunction);
      function myFunction(ev)
          var ddl = ev.target;
          var props = ddl.properties;
          if(props.hasOwnProperty('name'))
               switch(props.name)
                    case 'ddList1':
                        alert ('change made in ddList1');
                    break;
                    case 'ddList2':
                        alert ('change made in ddList2');
                    break;
                    case 'ddList3':
                        alert ('change made in ddList3');
                    break;
          ddl = null;
          props = null;
     dlg.show();

Answer 1

Thank you, that works perfectly. Is it because invoking the function using this method
myDDList1.onChange = myFunction;
the onChange Event actually contains a copy of myFunction(), and the this keyword used in the function is a reference to the element the onChange event is registered to; in this case myDDList1? Whereas, invoking the function using this method
myDDList1.addEventListenter('change', myFunction);
myFunction() is not copied, but only referred to when the onChange event happens? Still not sure why it wouldn't work, though. Mousedown, mouseover, and other Events trigger the function using this method and event.target can be used to refer to the element that triggered the Event.
Thanks again!