ItemMouseOut プロパティ

// The client event 'ItemMouseOut' takes two parameters sender and e
// sender  is the object which is raising the event
// e is the DropDownControlEventArgs
 
  function WebDropDown_ItemMouseOut(sender, e) {

     //Gets the drop-down item that has mouse out of it
      var item = e.get_value();

      //Gets the text of the drop-down item
      var text = item.get_text();

      //Gets the index of the drop-down item
      var index = item.get_index();
      alert("Mouse is out of the drop-down item '" + text + "' at index " + index);  
  }