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hashchange | onhashchange event

Raised when there are changes to the portion of a URL that follows the number sign (#).

This event is not supported for Windows Store apps using JavaScript.

Internet Explorer 8



HTML Attribute <element onhashchange = "handler(event)">
Event Property object.onhashchange = handler;
attachEvent Method object.attachEvent("onhashchange", handler)
addEventListener Method object.addEventListener("hashchange", handler, useCapture)


Event information



Event handler parameters

pEvtObj [in]

Type: IHTMLEventObj

Standards information

There are no standards that apply here.


In Asynchronous JavaScript and XML (AJAX) applications, client requests that do not trigger traditional page navigation should update the hash property. This lets the Back button function more predictably. The URL fragment (bookmark) can be set by script. The value is appended to the displayed URL, and the navigation is saved in the browser history.

Windows Internet Explorer 8. The browser's Back and Forward buttons do not generate onhashchange events for frames or iframes; instead, the frame is refreshed each time. Web pages hosted in frames or iframes should use their onload handler or equivalent to read the current URL hash information from the location. hash property and set their states accordingly.

When first navigating to a page that contains a hash identifier in the URL, an onhashchange event is not fired. It is expected that the freshly loaded page can inspect the value of the location. hash property to extract the current hash value. After this first page loads, setting the hash property will fire the onhashchange event as expected. This behavior avoids any negative impact on Web page load performance by removing a possible redundant event.

To invoke this event, do one of the following:

  • Set the location. hash (bookmark) property.
  • Navigate to the same page with a different bookmark.

The pEvtObj parameter is required for the following interfaces:


Attaching an event handler to a new onhashchange event enables the page to detect when the hash has changed and an AJAX navigation has occurred. See Introducing AJAX Navigations for a more robust example.

<body onhashchange="HashChangeHandler();">

See also

Introducing AJAX Navigations