The WindowEventHandlers.onhashchange property of the WindowEventHandlers mixin is the EventHandler for processing hashchange events.

The hashchange event fires when a window's hash changes (see Window.location and HTMLHyperlinkElementUtils.hash).


Using an event handler:

window.onhashchange = funcRef;

Using an HTML event handler:

<body onhashchange="funcRef();">

Using an event listener:

To add an event listener, use addEventListener():

window.addEventListener("hashchange", funcRef, false);


A reference to a function.


Using an event handler

This example uses an event handler (window.onhashchange) to check the new hash value whenever it changes. If it equals #cool-feature, the script logs a message to the console.

function locationHashChanged() {
  if (location.hash === '#cool-feature') {
    console.log("You're visiting a cool feature!");

window.onhashchange = locationHashChanged;

Using an event listener

This example uses an event listener to log a notification whenever the hash has changed.

function hashHandler() {
  console.log('The hash has changed!');

window.addEventListener('hashchange', hashHandler, false);

Overriding the hash

This function sets a new hash dynamically, setting it randomly to one of two values.

function changeHash() {
  location.hash = (Math.random() > 0.5) ? 'location1' : 'location2';

The hashchange event

The dispatched hashchange event has the following properties:

Field Type Description
newURL DOMString The new URL to which the window is navigating.
oldURL DOMString The previous URL from which the window was navigated.

Polyfill for event.newURL and event.oldURL

// Let this snippet run before your hashchange event binding code
if (!window.HashChangeEvent)(function(){
  var lastURL = document.URL;
  window.addEventListener("hashchange", function(event){
    Object.defineProperty(event, "oldURL", {enumerable:true,configurable:true,value:lastURL});
    Object.defineProperty(event, "newURL", {enumerable:true,configurable:true,value:document.URL});
    lastURL = document.URL;


Specification Status Comment
HTML Living Standard
The definition of 'onhashchange' in that specification.
Living Standard
HTML 5.1
The definition of 'GlobalEventHandlers' in that specification.
The definition of 'GlobalEventHandlers' in that specification.

Browser compatibility

BCD tables only load in the browser

See also