WebDropDown1.ClientEvents.DropDownOpening = "WebDropDown_DropDownOpening"
WebDropDown1.ClientEvents.DropDownOpening = "WebDropDown_DropDownOpening";
// The client event 'DropDownOpening' takes two parameters sender and e // sender is the object which is raising the event // e is the DropDownContainerEventArgs function WebDropDown_DropDownOpening(sender, e) { if (!confirm("Are you sure you want to open the drop-down container?")) //Cancels the DropDownOpening event e.set_cancel(true); }