The onloadstart property of the GlobalEventHandlers mixin is an EventHandler representing the code to be called when the loadstart event is raised (when progress has begun on the loading of a resource.)


img.onloadstart = funcRef;


funcRef is the handler function to be called when the resource's loadstart event fires.


HTML content

<img src="myImage.jpg">

JavaScript content

// 'loadstart' fires first, then 'load', then 'loadend'

image.addEventListener('load', function(e) {
  console.log('Image loaded');

image.addEventListener('loadstart', function(e) {
  console.log('Image load started');

image.addEventListener('loadend', function(e) {
  console.log('Image load finished');


Specification Status Comment
HTML Living Standard
The definition of 'onloadstart' in that specification.
Living Standard Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes11252 Yes Yes1 Yes1
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes1 Yes11252 Yes1 Yes1 Yes1

1. The loadstart event is not fired on <img> elements.

Document Tags and Contributors

Contributors to this page: fscholz, niklasHagner, Sebastianz, chrisdavidmills
Last updated by: fscholz,