Sys.UI.DomEvent removeHandler Method
Removes a DOM event handler from the DOM element that exposes the event. This member is static and can be invoked without creating an instance of the class.
Use the removeHandler method to remove a DOM event handler from the element that exposes the event. The eventName parameter should not include the "on" prefix. For example, specify "click" instead of "onclick".
This method can be accessed through the $removeHandler shortcut method.