/**
	 *  jQuery.observeHashChange (Version: 1.0)
	 *
	 *  http://finnlabs.github.com/jquery.observehashchange/
	 *
	 *  Copyright (c) 2009, Gregor Schmidt, Finn GmbH
	 *
	 *  Permission is hereby granted, free of charge, to any person obtaining a
	 *  copy of this software and associated documentation files (the "Software"),
	 *  to deal in the Software without restriction, including without limitation
	 *  the rights to use, copy, modify, merge, publish, distribute, sublicense,
	 *  and/or sell copies of the Software, and to permit persons to whom the
	 *  Software is furnished to do so, subject to the following conditions:
	 *
	 *  The above copyright notice and this permission notice shall be included in
	 *  all copies or substantial portions of the Software.
	 *
	 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	 *  DEALINGS IN THE SOFTWARE.
	 **/
	(function($) {
	  $.fn.hashchange = function(fn) {
	    $(window).bind("jQuery.hashchange", fn);
	    return this;
	  };

	  $.observeHashChange = function(options) {
	    var opts = $.extend({}, $.observeHashChange.defaults, options);
	    if (isHashChangeEventSupported()) {
	      	nativeVersion();
	    }
	    else {
	      setIntervalVersion(opts);
	    }
	  };

	  var locationHash = null;
	  var functionStore = null;
	  var interval = 0;

	  $.observeHashChange.defaults = {
	    interval : 500
	  };

	  function isHashChangeEventSupported() {
	    return "onhashchange" in window;
	  }

	  function nativeVersion() {
	    locationHash = document.location.hash;
	    window.onhashchange = onhashchangeHandler;
	  }

	  function onhashchangeHandler(e, data) {
	    var oldHash = locationHash;
	    locationHash = document.location.hash;
	    $(window).trigger("jQuery.hashchange", {before: oldHash, after: locationHash});
	  }

	  function setIntervalVersion(opts) {
	    if (locationHash == null) {
	      locationHash = document.location.hash;
	    }
	    if (functionStore != null) {
	      clearInterval(functionStore);
	    }
	    if (interval != opts.interval) {
	      functionStore = setInterval(checkLocationHash, opts.interval); 
	      interval = opts.interval;
	    }
	  }

	  function checkLocationHash() {
	    if (locationHash != document.location.hash) {
	      var oldHash = locationHash;
	      locationHash = document.location.hash;
	      $(window).trigger("jQuery.hashchange", {before: oldHash, after: locationHash});
	    }
	  }

	  $.observeHashChange();
	})(jQuery);