Raises events for the System.Web.UI.WebControls.ImageMap control when a form is posted back to the server.
The page passes the value of the eventArgument parameter to the ImageMap.RaisePostBackEvent(string) method of the System.Web.UI.WebControls.ImageMap control. The System.Web.UI.WebControls.ImageMap raises a ImageMap.Click event for the System.Web.UI.WebControls.HotSpot object that was clicked.