Element.addEventListener( ): register an event handler — DOM Level 2 Events:


void addEventListener(Stringtype,
                      Function listener,
                      boolean useCapture);



The type of event for which the event listener is to be invoked. For example, “load”, “click”, or “mousedown”.


The event-listener function that is invoked when an event of the specified type is dispatched to this element. When invoked, this listener function is passed an Event object and is invoked as a method of the element on which it is registered.


If true, the specified listener is to be invoked only during the capturing phase of event propagation. The more common value of false means that the listener is not invoked during the capturing phase but instead is invoked when this node is the actual event target or when the event bubbles up to this node from its original target.


This method adds the specified event-listener function to the set of listeners registered on this node to handle events of the specified type. If useCapture is true, the listener is registered as a capturing event listener. If useCapture is false, it is registered as a normal event listener.

addEventListener( ) may be called multiple times to register multiple event handlers for the same type of event on the same node. Note, however, that the DOM makes no guarantees about the order in which multiple event handlers are invoked.

If the same event-listener function is registered twice on the same node with ...

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