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   1  /*
   2  YUI 3.17.2 (build 9c3c78e)
   3  Copyright 2014 Yahoo! Inc. All rights reserved.
   4  Licensed under the BSD License.
   5  http://yuilibrary.com/license/
   6  */
   7  
   8  YUI.add('history-hash-ie', function (Y, NAME) {
   9  
  10  /**
  11   * Improves IE6/7 support in history-hash by using a hidden iframe to create
  12   * entries in IE's browser history. This module is only needed if IE6/7 support
  13   * is necessary; it's not needed for any other browser.
  14   *
  15   * @module history
  16   * @submodule history-hash-ie
  17   * @since 3.2.0
  18   */
  19  
  20  // Combination of a UA sniff to ensure this is IE (or a browser that wants us to
  21  // treat it like IE) and feature detection for native hashchange support (false
  22  // for IE < 8 or IE8/9 in IE7 mode).
  23  if (Y.UA.ie && !Y.HistoryBase.nativeHashChange) {
  24      var Do          = Y.Do,
  25          GlobalEnv   = YUI.namespace('Env.HistoryHash'),
  26          HistoryHash = Y.HistoryHash,
  27  
  28          iframe = GlobalEnv._iframe,
  29          win    = Y.config.win;
  30  
  31      /**
  32       * Gets the raw (not decoded) current location hash from the IE iframe,
  33       * minus the preceding '#' character and the hashPrefix (if one is set).
  34       *
  35       * @method getIframeHash
  36       * @return {String} current iframe hash
  37       * @static
  38       */
  39      HistoryHash.getIframeHash = function () {
  40          if (!iframe || !iframe.contentWindow) {
  41              return '';
  42          }
  43  
  44          var prefix = HistoryHash.hashPrefix,
  45              hash   = iframe.contentWindow.location.hash.substr(1);
  46  
  47          return prefix && hash.indexOf(prefix) === 0 ?
  48                      hash.replace(prefix, '') : hash;
  49      };
  50  
  51      /**
  52       * Updates the history iframe with the specified hash.
  53       *
  54       * @method _updateIframe
  55       * @param {String} hash location hash
  56       * @param {Boolean} replace (optional) if <code>true</code>, the current
  57       *   history state will be replaced without adding a new history entry
  58       * @protected
  59       * @static
  60       * @for HistoryHash
  61       */
  62      HistoryHash._updateIframe = function (hash, replace) {
  63          var iframeDoc      = iframe && iframe.contentWindow && iframe.contentWindow.document,
  64              iframeLocation = iframeDoc && iframeDoc.location;
  65  
  66          if (!iframeDoc || !iframeLocation) {
  67              return;
  68          }
  69  
  70  
  71          if (replace) {
  72              iframeLocation.replace(hash.charAt(0) === '#' ? hash : '#' + hash);
  73          } else {
  74              iframeDoc.open().close();
  75              iframeLocation.hash = hash;
  76          }
  77      };
  78  
  79      Do.before(HistoryHash._updateIframe, HistoryHash, 'replaceHash', HistoryHash, true);
  80  
  81      if (!iframe) {
  82          Y.on('domready', function () {
  83              var lastUrlHash = HistoryHash.getHash();
  84  
  85              // Create a hidden iframe to store history state, following the
  86              // iframe-hiding recommendations from
  87              // http://www.paciellogroup.com/blog/?p=604.
  88              //
  89              // This iframe will allow history navigation within the current page
  90              // context. After navigating to another page, all but the most
  91              // recent history state will be lost.
  92              //
  93              // Earlier versions of the YUI History Utility attempted to work
  94              // around this limitation by having the iframe load a static
  95              // resource. This workaround was extremely fragile and tended to
  96              // break frequently (and silently) since it was entirely dependent
  97              // on IE's inconsistent handling of iframe history.
  98              //
  99              // Since this workaround didn't work much of the time anyway and
 100              // added significant complexity, it has been removed, and IE6 and 7
 101              // now get slightly degraded history support.
 102  
 103              iframe = GlobalEnv._iframe = Y.Node.getDOMNode(Y.Node.create(
 104                  '<iframe src="javascript:0" style="display:none" height="0" width="0" tabindex="-1" title="empty"/>'
 105              ));
 106  
 107              // Append the iframe to the documentElement rather than the body.
 108              // Keeping it outside the body prevents scrolling on the initial
 109              // page load (hat tip to Ben Alman and jQuery BBQ for this
 110              // technique).
 111              Y.config.doc.documentElement.appendChild(iframe);
 112  
 113              // Update the iframe with the initial location hash, if any. This
 114              // will create an initial history entry that the user can return to
 115              // after the state has changed.
 116              HistoryHash._updateIframe(lastUrlHash || '#');
 117  
 118              // Listen for hashchange events and keep the iframe's hash in sync
 119              // with the parent frame's hash.
 120              Y.on('hashchange', function (e) {
 121                  lastUrlHash = e.newHash;
 122  
 123                  if (HistoryHash.getIframeHash() !== lastUrlHash) {
 124                      HistoryHash._updateIframe(lastUrlHash);
 125                  }
 126              }, win);
 127  
 128              // Watch the iframe hash in order to detect back/forward navigation.
 129              Y.later(50, null, function () {
 130                  var iframeHash = HistoryHash.getIframeHash();
 131  
 132                  if (iframeHash !== lastUrlHash) {
 133                      HistoryHash.setHash(iframeHash);
 134                  }
 135              }, null, true);
 136          });
 137      }
 138  }
 139  
 140  
 141  }, '3.17.2', {"requires": ["history-hash", "node-base"]});