onload Event
Example
Execute a JavaScript immediately after a page has been loaded:
<body onload="myFunction()">
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More "Try it Yourself" examples below.
Definition and Usage
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 JavaScript, using the addEventListener() method:
object.addEventListener("load", myScript);
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Note: The addEventListener() method is not supported in Internet Explorer 8 and earlier versions.
Technical Details
| Bubbles: | No |
|---|---|
| Cancelable: | No |
| Event type: | UiEvent if generated from a user interface, Event otherwise. |
| Supported 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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