W3cubDocs

/DOM

GlobalEventHandlers.onload

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

Feature	Chrome	Edge	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	(Yes)	(Yes)	?	?	?	?

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