/*! * Copyright (c) 2009 Andreas Blixt * Contributors: Aaron Ogle * This and more JavaScript libraries: http://blixt.org/js * MIT License: http://www.opensource.org/licenses/mit-license.php * * Hash handler * Keeps track of the history of changes to the hash part in the address bar. */ /* WARNING for Internet Explorer 7 and below: * If an element on the page has the same ID as the hash used, the history will * get messed up. * * Does not support history in Safari 2 and below. * * Example: * function handler(newHash) { * alert('Hash changed to "' + newHash + '"'); * } * Hash.init(handler, document.getElementById('hidden-iframe')); * Hash.go('abc123'); * * Updated by Aaron Ogle (aogle@avencia.com) on 8/11/2009 to: * - Fix bug where Firefox automatically unescapes location.hash but no other * browsers do. Always get the hash by parsing location.href and never use * location.hash. */ var LocationHash = (function () { var // Import globals window = this, documentMode = document.documentMode, history = window.history, location = window.location, // Plugin variables callback, hash, // IE-specific iframe, getHash = function () { // Internet Explorer 6 (and possibly other browsers) extracts the query // string out of the location.hash property into the location.search // property, so we can't rely on it. The location.search property can't be // relied on either, since if the URL contains a real query string, that's // what it will be set to. The only way to get the whole hash is to parse // it from the location.href property. // // Another thing to note is that in Internet Explorer 6 and 7 (and possibly // other browsers), subsequent hashes are removed from the location.href // (and location.hash) property if the location.search property is set. // // Via Aaron: Firefox 3.5 (and below?) always unescape location.hash which // causes poll to fire the hashchange event twice on escaped hashes. This is // because the hash variable (escaped) will not match location.hash // (unescaped.) The only consistent option is to rely completely on // location.href. var index = location.href.indexOf('#'); return (index == -1 ? '' : location.href.substr(index + 1)); }, // Used by all browsers except Internet Explorer 7 and below. poll = function () { var curHash = getHash(); if (curHash != hash) { hash = curHash; callback(curHash); } }, // Used to create a history entry with a value in the iframe. setIframe = function (newHash) { try { var doc = iframe.contentWindow.document; doc.open(); doc.write('' + newHash + ''); doc.close(); hash = newHash; } catch (e) { setTimeout(function () { setIframe(newHash); }, 10); } }, // Used by Internet Explorer 7 and below to set up an iframe that keeps track // of history changes. setUpIframe = function () { // Don't run until access to the iframe is allowed. try { iframe.contentWindow.document; } catch (e) { setTimeout(setUpIframe, 10); return; } // Create a history entry for the initial state. setIframe(hash); var data = hash; setInterval(function () { var curData, curHash; try { curData = iframe.contentWindow.document.body.innerText; if (curData != data) { data = curData; location.hash = hash = curData; callback(curData); } else { curHash = getHash(); if (curHash != hash) setIframe(curHash); } } catch (e) { } }, 50); }; return { init: function (cb, ifr) { // init can only be called once. if (callback) return; callback = cb; // Keep track of the hash value. hash = getHash(); cb(hash); // Run specific code for Internet Explorer. if (window.ActiveXObject) { if (!documentMode || documentMode < 8) { // Internet Explorer 5.5/6/7 need an iframe for history // support. iframe = ifr; setUpIframe(); } else { // Internet Explorer 8 has onhashchange event. window.attachEvent('onhashchange', poll); } } else { // Change Opera navigation mode to improve history support. if (history.navigationMode) history.navigationMode = 'compatible'; setInterval(poll, 50); } }, go: function (newHash) { // Cancel if the new hash is the same as the current one, since there // is no cross-browser way to keep track of navigation to the exact // same hash multiple times in a row. A wrapper can handle this by // adding an incrementing counter to the end of the hash. if (newHash == hash) return; if (iframe) { setIframe(newHash); } else { location.hash = hash = newHash; callback(newHash); } } }; })();