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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

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes Yes Yes Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes Yes Yes Yes Yes

See also