safariPolyfill.js

// Safari, in Private Browsing Mode, looks like it supports localStorage but all calls to setItem
// throw QuotaExceededError. We're going to detect this and just silently drop any calls to setItem
// to avoid the entire page breaking, without having to do a check at each usage of Storage.
if (typeof window.localStorage === 'object') {
    try {
        window.localStorage.setItem('localStorage', 1);
        window.localStorage.removeItem('localStorage');
    } catch (e) {
	(function () {
		var Storage = function (type) {
			function createCookie(name, value, days) {
				var date, expires;

				if (days) {
					date = new Date();
					date.setTime(date.getTime()+(days*24*60*60*1000));
					expires = "; expires="+date.toGMTString();
				} else {
					expires = "";
				}
				document.cookie = name+"="+value+expires+"; path=/";
			}

			function readCookie(name) {
				var nameEQ = name + "=",
					ca = document.cookie.split(';'),
					i, c;

				for (i=0; i < ca.length; i++) {
					c = ca[i];
					while (c.charAt(0)==' ') {
						c = c.substring(1,c.length); 
					}

					if (c.indexOf(nameEQ) == 0) {
						return c.substring(nameEQ.length,c.length);
					}
				}
				return null;
			}

			function setData(data) {
				// Convert data into JSON and encode to accommodate for special characters.
				data = encodeURIComponent(JSON.stringify(data));
				// Create cookie.
				if (type == 'session') {
					createCookie(getSessionName(), data, 365);
				} else {
					createCookie('localStorage', data, 365);
				}
			}

			function clearData() {
				if (type == 'session') {
					createCookie(getSessionName(), '', 365);
				} else {
					createCookie('localStorage', '', 365);
				}
			}

			function getData() {
				// Get cookie data.
				var data = type == 'session' ? readCookie(getSessionName()) : readCookie('localStorage');
				// If we have some data decode, parse and return it.
				return data ? JSON.parse(decodeURIComponent(data)) : {};
			}

			function getSessionName() {
				// If there is no name for this window, set one.
				// To ensure it's unquie use the current timestamp.
				if(!window.name) {
					window.name = new Date().getTime();
				}
				return 'sessionStorage' + window.name;
			}

			// Initialise if there's already data.
			var data = getData();

			return {
				length: 0,
				clear: function () {
					data = {};
					this.length = 0;
					clearData();
				},
				getItem: function (key) {
					return data[key] === undefined ? null : data[key];
				},
				key: function (i) {
					// not perfect, but works
					var ctr = 0;
					for (var k in data) {
						if (ctr == i) return k;
						else ctr++;
					}
					return null;
				},
				removeItem: function (key) {
					delete data[key];
					this.length--;
					setData(data);
				},
				setItem: function (key, value) {
					data[key] = value+''; // forces the value to a string
					this.length++;
					setData(data);
				}
			};
		};

		// Replace window.localStorage and window.sessionStorage with out custom
		// implementation.
		var localStorage = new Storage('local');
		var sessionStorage = new Storage('session');
		window.localStorage = localStorage;
		window.sessionStorage = sessionStorage;
		// For Safari private browsing need to also set the proto value.
		window.localStorage.__proto__ = localStorage;
		window.sessionStorage.__proto__ = sessionStorage;
	})();
    }
}