onload Event

Example

Execute a JavaScript immediately after a page has been loaded:

More "Try it Yourself" examples below.

Description

The onload event occurs when an object has been loaded.

onload is most often used within the <body> element to execute a script once a web page has completely loaded all content (including images, script files, CSS files, etc.).

The onload event can be used to check the visitor's browser type and browser version, and load the proper version of the web page based on the information.

The onload event can also be used to deal with cookies (see "More Examples" below).

Browser Support

Event
onload	Yes	Yes	Yes	Yes	Yes

Syntax

In HTML:

< element onload=" myScript">

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In JavaScript:

object.onload = function(){ myScript};

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In JavaScript, using the addEventListener() method:

object.addEventListener("load", myScript);

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Technical Details

Bubbles:	No
Cancelable:	No
Event type:	UiEvent if generated from a user interface, Event otherwise.
HTML tags:	<body>, <frame>, <iframe>, <img>, <input type="image">, <link>, <script>, <style>
DOM Version:	Level 2 Events

More Examples

Example

Using onload on an <img> element. Alert "Image is loaded" immediately after an image has been loaded:

<img src="w3javascript.gif" onload="loadImage()" width="100" height="132">

<script>
function loadImage() {
alert("Image is loaded");
}
</script>

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Example

Using the onload event to deal with cookies:

<body onload="checkCookies()">

<script>
function checkCookies() {
  var text = "";

if (navigator.cookieEnabled == true) {
    text = "Cookies are enabled.";
  } else {
     text = "Cookies are not enabled.";
  }
  document.getElementById("demo").innerHTML = text;
}
</script>

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