The onload property of the GlobalEventHandlers mixin is an event handler for the load event of a Window, XMLHttpRequest, <img> element, etc., which fires when the resource has loaded.
Syntax
window.onload = funcRef;
Value
funcRef is the handler function to be called when the window’s load event fires.
Examples
window.onload = function() {
init();
doSomethingElse();
};
<!doctype html>
<html>
<head>
<title>onload test</title>
// ES5
<script>
function load() {
console.log("load event detected!");
}
window.onload = load;
</script>
// ES2015
<script>
const load = () => {
console.log("load event detected!");
}
window.onload = load;
</script>
</head>
<body>
<p>The load event fires when the document has finished loading!</p>
</body>
</html>
Notes
The load event fires at the end of the document loading process. At this point, all of the objects in the document are in the DOM, and all the images, scripts, links and sub-frames have finished loading.
There are also Gecko-Specific DOM Events like DOMContentLoaded and DOMFrameContentLoaded (which can be handled using EventTarget.addEventListener()) which are fired after the DOM for the page has been constructed, but do not wait for other resources to finish loading.
Specifications
| Specification | Status | Comment |
|---|---|---|
| HTML Living Standard The definition of 'onload' in that specification. |
Living Standard | Initial definition |
Browser compatibility
| Desktop | Mobile | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basic support | Chrome Full support Yes | Edge Full support Yes | Firefox Full support Yes | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Edge Mobile Full support Yes | Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
See also
DOMContentLoadedevent in Listening to events: Simple DOM events- IIFE Immediately-invoked function expression