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
WHATWG HTML Living Standard
The definition of 'onload' in that specification.
Living Standard Initial definition

Browser Compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (Yes) ? ? ? ?
Feature Android Android Webview Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support ? (Yes) ? ? ? ? ? (Yes)

See also