JS DOM: Add / Remove Event Handler

Add event handler

node.addEventListener(eventName, functionName)

Adds a event handler.

eventName is a string representing a event.

functionName is a function that will be called when the event happens.

The event handler function functionName is passed a eventObject as argument.

The element that fired the event can be accessed by eventObject.target.

Remove event handler

node.removeEventListener(eventName, functionName)

Remove the function that was attached to the event.

Example. click button

Here is a simple click event.

Code

<div id="xclick_tkvgQ">click me</div>

<p id="xoutput_kqy5B"></p>

const xclick_tkvgQ = document.getElementById("xclick_tkvgQ");

const xoutput_kqy5B = document.getElementById("xoutput_kqy5B");

const ff = (() => { xoutput_kqy5B.textContent = xoutput_kqy5B.textContent + "clicked "});

xclick_tkvgQ.addEventListener ("click", ff);

This is a simple example of a Event. The event is "click". When user clicks, the browser fires the event, then calls the function attached to that event. (function for this purpose is called the “event handler”.)