WebDropDown1.ClientEvents.ValueChanging = "WebDropDown_ValueChanging"
WebDropDown1.ClientEvents.ValueChanging = "WebDropDown_ValueChanging";
// The client event 'ValueChanging' takes two parameters sender and e // sender is the object which is raising the event // e is the DropDownEditEventArgs function WebDropDown_ValueChanging(sender, e) { //Gets the new value in the value display var newValue = e.getNewValue(); //Gets the old value in the value display var oldValue = e.getOldValue(); if (!confirm("Are you sure you want to change the curent value from '"+ oldValue+"' to"+newValue+"?")) //Cancels the ValueChanging client event e.set_cancel(true); }