THE WORLD'S LARGEST WEB DEVELOPER SITE

JS Tutorial

JS HOME JS Introduction JS Where To JS Output JS Statements JS Syntax JS Comments JS Variables JS Operators JS Arithmetic JS Assignment JS Data Types JS Functions JS Objects JS Events JS Strings JS String Methods JS Numbers JS Number Methods JS Arrays JS Array Methods JS Array Sort JS Array Iteration JS Dates JS Date Formats JS Date Get Methods JS Date Set Methods JS Math JS Random JS Booleans JS Comparisons JS Conditions JS Switch JS Loop For JS Loop While JS Break JS Type Conversion JS Bitwise JS RegExp JS Errors JS Scope JS Hoisting JS Strict Mode JS this Keyword JS Let JS Const JS Arrow Function JS Classes JS Debugging JS Style Guide JS Best Practices JS Mistakes JS Performance JS Reserved Words JS Versions JS Version ES5 JS Version ES6 JS JSON

JS Forms

JS Forms Forms API

JS Objects

Object Definitions Object Properties Object Methods Object Accessors Object Constructors Object Prototypes Object ECMAScript 5

JS Functions

Function Definitions Function Parameters Function Invocation Function Call Function Apply Function Closures

JS HTML DOM

DOM Intro DOM Methods DOM Document DOM Elements DOM HTML DOM CSS DOM Animations DOM Events DOM Event Listener DOM Navigation DOM Nodes DOM Collections DOM Node Lists

JS Browser BOM

JS Window JS Screen JS Location JS History JS Navigator JS Popup Alert JS Timing JS Cookies

JS AJAX

AJAX Intro AJAX XMLHttp AJAX Request AJAX Response AJAX XML File AJAX PHP AJAX ASP AJAX Database AJAX Applications AJAX Examples

JS JSON

JSON Intro JSON Syntax JSON vs XML JSON Data Types JSON Parse JSON Stringify JSON Objects JSON Arrays JSON PHP JSON HTML JSON JSONP

JS vs jQuery

jQuery Selectors jQuery HTML jQuery CSS jQuery DOM

JS Examples

JS Examples JS HTML DOM JS HTML Input JS HTML Objects JS HTML Events JS Browser JS Exercises JS Quiz JS Certificate

JS References

JavaScript Objects HTML DOM Objects


JavaScript HTML DOM EventListener


The addEventListener() method

Example

Add an event listener that fires when a user clicks a button:

document.getElementById("myBtn").addEventListener("click", displayDate);
Try it Yourself »

The addEventListener() method attaches an event handler to the specified element.

The addEventListener() method attaches an event handler to an element without overwriting existing event handlers.

You can add many event handlers to one element.

You can add many event handlers of the same type to one element, i.e two "click" events.

You can add event listeners to any DOM object not only HTML elements. i.e the window object.

The addEventListener() method makes it easier to control how the event reacts to bubbling.

When using the addEventListener() method, the JavaScript is separated from the HTML markup, for better readability and allows you to add event listeners even when you do not control the HTML markup.

You can easily remove an event listener by using the removeEventListener() method.


Syntax

element.addEventListener(event, function, useCapture);

The first parameter is the type of the event (like "click" or "mousedown" or any other HTML DOM Event.)

The second parameter is the function we want to call when the event occurs.

The third parameter is a boolean value specifying whether to use event bubbling or event capturing. This parameter is optional.

Note that you don't use the "on" prefix for the event; use "click" instead of "onclick".


Add an Event Handler to an Element

Example

Alert "Hello World!" when the user clicks on an element:

element.addEventListener("click", function(){ alert("Hello World!"); });
Try it Yourself »

You can also refer to an external "named" function:

Example

Alert "Hello World!" when the user clicks on an element:

element.addEventListener("click", myFunction);

function myFunction() {
  alert ("Hello World!");
}
Try it Yourself »


Add Many Event Handlers to the Same Element

The addEventListener() method allows you to add many events to the same element, without overwriting existing events:

Example

element.addEventListener("click", myFunction);
element.addEventListener("click", mySecondFunction);
Try it Yourself »

You can add events of different types to the same element:

Example

element.addEventListener("mouseover", myFunction);
element.addEventListener("click", mySecondFunction);
element.addEventListener("mouseout", myThirdFunction);
Try it Yourself »

Add an Event Handler to the window Object

The addEventListener() method allows you to add event listeners on any HTML DOM object such as HTML elements, the HTML document, the window object, or other objects that support events, like the xmlHttpRequest object.

Example

Add an event listener that fires when a user resizes the window:

window.addEventListener("resize", function(){
  document.getElementById("demo").innerHTML = sometext;
});
Try it Yourself »

Passing Parameters

When passing parameter values, use an "anonymous function" that calls the specified function with the parameters:

Example

element.addEventListener("click", function(){ myFunction(p1, p2); });
Try it Yourself »

Event Bubbling or Event Capturing?

There are two ways of event propagation in the HTML DOM, bubbling and capturing.

Event propagation is a way of defining the element order when an event occurs. If you have a <p> element inside a <div> element, and the user clicks on the <p> element, which element's "click" event should be handled first?

In bubbling the inner most element's event is handled first and then the outer: the <p> element's click event is handled first, then the <div> element's click event.

In capturing the outer most element's event is handled first and then the inner: the <div> element's click event will be handled first, then the <p> element's click event.

With the addEventListener() method you can specify the propagation type by using the "useCapture" parameter:

addEventListener(event, function, useCapture);

The default value is false, which will use the bubbling propagation, when the value is set to true, the event uses the capturing propagation.

Example

document.getElementById("myP").addEventListener("click", myFunction, true);
document.getElementById("myDiv").addEventListener("click", myFunction, true);
Try it Yourself »

The removeEventListener() method

The removeEventListener() method removes event handlers that have been attached with the addEventListener() method:

Example

element.removeEventListener("mousemove", myFunction);
Try it Yourself »

Browser Support

The numbers in the table specifies the first browser version that fully supports these methods.

Method
addEventListener() 1.0 9.0 1.0 1.0 7.0
removeEventListener() 1.0 9.0 1.0 1.0 7.0

Note: The addEventListener() and removeEventListener() methods are not supported in IE 8 and earlier versions. However, for these specific browser versions, you can use the attachEvent() method to attach an event handlers to the element, and the detachEvent() method to remove it:

element.attachEvent(event, function);
element.
detachEvent(event, function);

Example

Cross-browser solution:

var x = document.getElementById("myBtn");
if (x.addEventListener) {     // For all major browsers, except IE 8 and earlier
  x.addEventListener("click", myFunction);
} else if (x.attachEvent) {   // For IE 8 and earlier versions
  x.attachEvent("onclick", myFunction);
}
Try it Yourself »

HTML DOM Event Object Reference

For a list of all HTML DOM events, look at our complete HTML DOM Event Object Reference.


Test Yourself With Exercises

Exercise:

Use the eventListener to assign an onclick event to the <button> element.

<button id="demo"></button>

<script>
document.getElementById("demo").("", myFunction);
</script>

Start the Exercise