Javascript button event listener

JavaScript HTML DOM EventListener

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

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

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:

You can also refer to an external «named» function:

Example

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

function myFunction() alert («Hello World!»);
>

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

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

Example

element.addEventListener(«mouseover», myFunction);
element.addEventListener(«click», mySecondFunction);
element.addEventListener(«mouseout», myThirdFunction);

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;
>);

Passing Parameters

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

Example

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

element inside a element, and the user clicks on the

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

element’s click event is handled first, then the element’s click event.

In capturing the outer most element’s event is handled first and then the inner: the element’s click event will be handled first, then the

element’s click event.

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

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);

The removeEventListener() method

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

Example

HTML DOM Event Object Reference

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

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Element: click event

An element receives a click event when a pointing device button (such as a mouse’s primary mouse button) is both pressed and released while the pointer is located inside the element.

If the button is pressed on one element and the pointer is moved outside the element before the button is released, the event is fired on the most specific ancestor element that contained both elements.

click fires after both the mousedown and mouseup events have fired, in that order.

Syntax

Use the event name in methods like addEventListener() , or set an event handler property.

addEventListener("click", (event) => >); onclick = (event) => >; 

Event type

Event properties

This interface also inherits properties of its parents, UIEvent and Event . MouseEvent.altKey Read only Returns true if the alt key was down when the mouse event was fired. MouseEvent.button Read only The button number that was pressed (if applicable) when the mouse event was fired. MouseEvent.buttons Read only The buttons being pressed (if any) when the mouse event was fired. MouseEvent.clientX Read only The X coordinate of the mouse pointer in local (DOM content) coordinates. MouseEvent.clientY Read only The Y coordinate of the mouse pointer in local (DOM content) coordinates. MouseEvent.ctrlKey Read only Returns true if the control key was down when the mouse event was fired. MouseEvent.layerX Non-standard Read only Returns the horizontal coordinate of the event relative to the current layer. MouseEvent.layerY Non-standard Read only Returns the vertical coordinate of the event relative to the current layer. MouseEvent.metaKey Read only Returns true if the meta key was down when the mouse event was fired. MouseEvent.movementX Read only The X coordinate of the mouse pointer relative to the position of the last mousemove event. MouseEvent.movementY Read only The Y coordinate of the mouse pointer relative to the position of the last mousemove event. MouseEvent.offsetX Read only The X coordinate of the mouse pointer relative to the position of the padding edge of the target node. MouseEvent.offsetY Read only The Y coordinate of the mouse pointer relative to the position of the padding edge of the target node. MouseEvent.pageX Read only The X coordinate of the mouse pointer relative to the whole document. MouseEvent.pageY Read only The Y coordinate of the mouse pointer relative to the whole document. MouseEvent.relatedTarget Read only The secondary target for the event, if there is one. MouseEvent.screenX Read only The X coordinate of the mouse pointer in global (screen) coordinates. MouseEvent.screenY Read only The Y coordinate of the mouse pointer in global (screen) coordinates. MouseEvent.shiftKey Read only Returns true if the shift key was down when the mouse event was fired. MouseEvent.mozInputSource Non-standard Read only The type of device that generated the event (one of the MOZ_SOURCE_* constants). This lets you, for example, determine whether a mouse event was generated by an actual mouse or by a touch event (which might affect the degree of accuracy with which you interpret the coordinates associated with the event). MouseEvent.webkitForce Non-standard Read only The amount of pressure applied when clicking. MouseEvent.x Read only Alias for MouseEvent.clientX . MouseEvent.y Read only Alias for MouseEvent.clientY .

Usage notes

The MouseEvent object passed into the event handler for click has its detail property set to the number of times the target was clicked. In other words, detail will be 2 for a double-click, 3 for triple-click, and so forth. This counter resets after a short interval without any clicks occurring; the specifics of how long that interval is may vary from browser to browser and across platforms. The interval is also likely to be affected by user preferences; for example, accessibility options may extend this interval to make it easier to perform multiple clicks with adaptive interfaces.

Examples

HTML

JavaScript

const button = document.querySelector("button"); button.addEventListener("click", (event) =>  button.textContent = `Click count: $event.detail>`; >); 

Result

Try making rapid, repeated clicks on the button to increase the click count. If you take a break between clicks, the count will reset.

Specifications

Browser compatibility

See also

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This page was last modified on Jun 26, 2023 by MDN contributors.

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