Me.WebTab1.ClientEvents.TabClosed = "WebTab1_TabClosed"
this.WebTab1.ClientEvents.TabClosed = "WebTab1_TabClosed";
// The client event TabClosed takes two parameters sender and e // sender is the object which is raising the event // e is the TabItemPostBackEventArgs function WebTab1_TabClosed(sender, e) { //Gets the index of the closed tab var tabIndex = e.get_tabIndex(); //Assuming you have a label called labelOutput on the form var label = $get('labelOutput'); label.innerHTML = ("Tab with index '" + tabIndex + "' is closed!"); }