Adds an event handler to this event endpoint.
"mouseEvent_var" is a variable referencing a MouseEvent object. |
"mouseEvent_var" is a variable referencing a MouseEvent object. |
| Type | Description |
| boolean | Returns true if the handler was successfully added to the set of event handlers. |
| Name | Type | Description |
| handler | MouseEventHandler | The client implemented MouseEventHandler to be called when this event is triggered. |