The XMLHttpRequestEventTarget.onload is the function called when an XMLHttpRequest transaction completes successfully.


XMLHttpRequest.onload = callback;


  • callback is the function to be executed when the request completes successfully. It receives a ProgressEvent object as its first argument. The value of this (i.e. the context) is the same XMLHttpRequest this callback is related to.


var xmlhttp = new XMLHttpRequest(),
  method = 'GET',
  url = 'https://developer.mozilla.org/';

xmlhttp.open(method, url, true);
xmlhttp.onload = function () {
  // Do something with the retrieved data ( found in xmlhttp.response )


Specification Status Comment
XMLHttpRequest Living Standard WHATWG living standard

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support 1 (Yes) 1.0 (1.7 or earlier) 7 (Yes) 1.2
Feature Android Chrome for Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? 1.0 (Yes) (Yes) ? ? ?


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 Last updated by: ChrisBrownie55,