jQuery hashchange event

Fired when location.hash changes.  In browsers that support it, the native HTML5 window.onhashchange event is used, otherwise a polling loop is initialized, running every jQuery.fn.hashchange.delay milliseconds to see if the hash has changed.  In IE6/7 (and IE8 operating in “IE7 compatibility” mode), a hidden Iframe is created to allow the back button and hash-based history to work.

Usage as described in jQuery.fn.hashchange

// Bind an event handler.
jQuery(window).hashchange( function(e) {
  var hash = location.hash;
  ...
});

// Manually trigger the event handler.
jQuery(window).hashchange();

A more verbose usage that allows for event namespacing

// Bind an event handler.
jQuery(window).bind( 'hashchange', function(e) {
  var hash = location.hash;
  ...
});

// Manually trigger the event handler.
jQuery(window).trigger( 'hashchange' );

Additional Notes

• The polling loop and Iframe are not created until at least one handler is actually bound to the ‘hashchange’ event.
• If you need the bound handler(s) to execute immediately, in cases where a location.hash exists on page load, via bookmark or page refresh for example, use jQuery(window).hashchange() or the more verbose jQuery(window).trigger( ‘hashchange’ ).
• The event can be bound before DOM ready, but since it won’t be usable before then in IE6/7 (due to the necessary Iframe), recommended usage is to bind it inside a DOM ready handler.