ActivationChanged プロパティ (DropDownClientEvents)

// The client event 'ActivationChanged' takes two parameters sender and e
// sender  is the object which is raising the event
// e is the DropDownActivationEventArgs

function WebDropDown_ActivationChanged(sender, e) {

    //Gets the new active DropDownItem object
    var newActiveItem = e.getNewActiveItem();

    //Gets the old active DropDownItem object
    var oldActiveItem = e.getOldActiveItem();

    //Gets the text of the new active item
    var newItemText = newActiveItem.get_text();

    if (oldActiveItem != null) {
       //Gets the text of the old active item
        var oldItemText = oldActiveItem.get_text();
        window.status = "New Active Item : " + newItemText + "; Old Active Item : " + oldItemText;

    } else {
        window.status = "New Active Item : " + newItemText;
    } 
}