/*!
 * Copyright 2012, Chris Wanstrath
 * Released under the MIT License
 * https://github.com/defunkt/jquery-pjax
 */

(function($) {

	// When called on a container with a selector, fetches the href with
	// ajax into the container or with the data-pjax attribute on the link
	// itself.
	//
	// Tries to make sure the back button and ctrl+click work the way
	// you'd expect.
	//
	// Exported as $.fn.pjax
	//
	// Accepts a jQuery ajax options object that may include these
	// pjax specific options:
	//
	//
	// container - String selector for the element where to place the response body.
	//      push - Whether to pushState the URL. Defaults to true (of course).
	//   replace - Want to use replaceState instead? That's cool.
	//
	// For convenience the second parameter can be either the container or
	// the options object.
	//
	// Returns the jQuery object
	function fnPjax(selector, container, options) {
		options = optionsFor(container, options);
		return this.on('click.pjax', selector, function(event) {
			var opts = options;
			if (!opts.container) {
				opts = $.extend({}, options);
				opts.container = $(this).attr('data-pjax');
			}
			handleClick(event, opts);
		});
	}

	// Public: pjax on click handler
	//
	// Exported as $.pjax.click.
	//
	// event   - "click" jQuery.Event
	// options - pjax options
	//
	// Examples
	//
	//   $(document).on('click', 'a', $.pjax.click)
	//   // is the same as
	//   $(document).pjax('a')
	//
	// Returns nothing.
	function handleClick(event, container, options) {
		options = optionsFor(container, options);

		var link = event.currentTarget;
		var $link = $(link);

		if (link.tagName.toUpperCase() !== 'A') {
			throw '$.fn.pjax or $.pjax.click requires an anchor element';
		}

		// Middle click, cmd click, and ctrl click should open
		// links in a new tab as normal.
		if (event.which > 1 || event.metaKey || event.ctrlKey || event.shiftKey || event.altKey) {
			return;
		}

		// Ignore cross origin links
		if (location.protocol !== link.protocol || location.hostname !== link.hostname) {
			return;
		}

		// Ignore case when a hash is being tacked on the current URL
		if (link.href.indexOf('#') > -1 && stripHash(link) == stripHash(location)) {
			return;
		}

		// Ignore event with default prevented
		if (event.isDefaultPrevented()) {
			return;
		}

		var defaults = {
			url      : link.href,
			container: $link.attr('data-pjax'),
			target   : link
		};

		var opts = $.extend({}, defaults, options);
		var clickEvent = $.Event('pjax:click');
		$link.trigger(clickEvent, [opts]);

		if (!clickEvent.isDefaultPrevented()) {
			pjax(opts);
			event.preventDefault();
			$link.trigger('pjax:clicked', [opts]);
		}
	}

	// Public: pjax on form submit handler
	//
	// Exported as $.pjax.submit
	//
	// event   - "click" jQuery.Event
	// options - pjax options
	//
	// Examples
	//
	//  $(document).on('submit', 'form', function(event) {
	//    $.pjax.submit(event, '[data-pjax-container]')
	//  })
	//
	// Returns nothing.
	function handleSubmit(event, container, options) {
		options = optionsFor(container, options);

		var form = event.currentTarget;
		var $form = $(form);

		if (form.tagName.toUpperCase() !== 'FORM') {
			throw '$.pjax.submit requires a form element';
		}

		var defaults = {
			type     : ($form.attr('method') || 'GET').toUpperCase(),
			url      : $form.attr('action'),
			container: $form.attr('data-pjax'),
			target   : form
		};

		if (defaults.type !== 'GET' && window.FormData !== undefined) {
			defaults.data = new FormData(form);
			defaults.processData = false;
			defaults.contentType = false;
		} else {
			// Can't handle file uploads, exit
			if ($form.find(':file').length) {
				return;
			}

			// Fallback to manually serializing the fields
			defaults.data = $form.serializeArray();
		}

		pjax($.extend({}, defaults, options));

		event.preventDefault();
	}

	// Loads a URL with ajax, puts the response body inside a container,
	// then pushState()'s the loaded URL.
	//
	// Works just like $.ajax in that it accepts a jQuery ajax
	// settings object (with keys like url, type, data, etc).
	//
	// Accepts these extra keys:
	//
	// container - String selector for where to stick the response body.
	//      push - Whether to pushState the URL. Defaults to true (of course).
	//   replace - Want to use replaceState instead? That's cool.
	//
	// Use it just like $.ajax:
	//
	//   var xhr = $.pjax({ url: this.href, container: '#main' })
	//   console.log( xhr.readyState )
	//
	// Returns whatever $.ajax returns.
	function pjax(options) {
		options = $.extend(true, {}, $.ajaxSettings, pjax.defaults, options);

		if (typeof options.url === 'function') {
			options.url = options.url();
		}

		var hash = parseURL(options.url).hash;

		var containerType = typeof options.container;
		if (containerType !== 'string') {
			throw 'expected string value for \'container\' option; got ' + containerType;
		}
		var context = options.context = $(options.container);
		if (!context.length) {
			throw 'the container selector \'' + options.container + '\' did not match anything';
		}

		// We want the browser to maintain two separate internal caches: one
		// for pjax'd partial page loads and one for normal page loads.
		// Without adding this secret parameter, some browsers will often
		// confuse the two.
		if (!options.data) {
			options.data = {};
		}
		if (Array.isArray(options.data)) {
			options.data.push({
				name : '_pjax',
				value: options.container
			});
		} else {
			options.data._pjax = options.container;
		}

		function fire(type, args, props) {
			if (!props) {
				props = {};
			}
			props.relatedTarget = options.target;
			var event = $.Event(type, props);
			context.trigger(event, args);
			return !event.isDefaultPrevented();
		}

		var timeoutTimer;

		options.beforeSend = function(xhr, settings) {
			// No timeout for non-GET requests
			// Its not safe to request the resource again with a fallback method.
			if (settings.type !== 'GET') {
				settings.timeout = 0;
			}

			xhr.setRequestHeader('X-PJAX', 'true');
			xhr.setRequestHeader('X-PJAX-Container', options.container);

			if (!fire('pjax:beforeSend', [
				xhr,
				settings
			])) {
				return false;
			}

			if (settings.timeout > 0) {
				timeoutTimer = setTimeout(function() {
					if (fire('pjax:timeout', [
						xhr,
						options
					])) {
						xhr.abort('timeout');
					}
				}, settings.timeout);

				// Clear timeout setting so jquerys internal timeout isn't invoked
				settings.timeout = 0;
			}

			var url = parseURL(settings.url);
			if (hash) {
				url.hash = hash;
			}
			options.requestUrl = stripInternalParams(url);
		};

		options.complete = function(xhr, textStatus) {
			if (timeoutTimer) {
				clearTimeout(timeoutTimer);
			}

			fire('pjax:complete', [
				xhr,
				textStatus,
				options
			]);

			fire('pjax:end', [
				xhr,
				options
			]);
		};

		options.error = function(xhr, textStatus, errorThrown) {
			var container = extractContainer('', xhr, options);

			var allowed = fire('pjax:error', [
				xhr,
				textStatus,
				errorThrown,
				options
			]);
			if (options.type == 'GET' && textStatus !== 'abort' && allowed) {
				locationReplace(container.url);
			}
		};

		options.success = function(data, status, xhr) {
			var previousState = pjax.state;

			// If $.pjax.defaults.version is a function, invoke it first.
			// Otherwise it can be a static string.
			var currentVersion = typeof $.pjax.defaults.version === 'function' ?
				$.pjax.defaults.version() :
				$.pjax.defaults.version;

			var latestVersion = xhr.getResponseHeader('X-PJAX-Version');

			var container = extractContainer(data, xhr, options);

			var url = parseURL(container.url);
			if (hash) {
				url.hash = hash;
				container.url = url.href;
			}

			// If there is a layout version mismatch, hard load the new url
			if (currentVersion && latestVersion && currentVersion !== latestVersion) {
				locationReplace(container.url);
				return;
			}

			// If the new response is missing a body, hard load the page
			if (!container.contents) {
				locationReplace(container.url);
				return;
			}

			pjax.state = {
				id       : options.id || uniqueId(),
				url      : container.url,
				title    : container.title,
				container: options.container,
				fragment : options.fragment,
				timeout  : options.timeout
			};

			if (options.push || options.replace) {
				window.history.replaceState(pjax.state, container.title, container.url);
			}

			// Only blur the focus if the focused element is within the container.
			var blurFocus = $.contains(context, document.activeElement);

			// Clear out any focused controls before inserting new page contents.
			if (blurFocus) {
				try {
					document.activeElement.blur();
				}
				catch (e) { /* ignore */
				}
			}

			if (container.title) {
				document.title = container.title;
			}

			fire('pjax:beforeReplace', [
				container.contents,
				options
			], {
				state        : pjax.state,
				previousState: previousState
			});

			if ('function' === typeof options.renderCallback) {
				options.renderCallback(context, container.contents, afterRender);
			} else {
				context.html(container.contents);
				afterRender();
			}

			function afterRender() {
				// FF bug: Won't autofocus fields that are inserted via JS.
				// This behavior is incorrect. So if theres no current focus, autofocus
				// the last field.
				//
				// http://www.w3.org/html/wg/drafts/html/master/forms.html
				var autofocusEl = context.find('input[autofocus], textarea[autofocus]').last()[0];
				if (autofocusEl && document.activeElement !== autofocusEl) {
					autofocusEl.focus();
				}

				executeScriptTags(container.scripts);

				var scrollTo = options.scrollTo;

				// Ensure browser scrolls to the element referenced by the URL anchor
				if (hash) {
					var name = decodeURIComponent(hash.slice(1));
					var target = document.getElementById(name) || document.getElementsByName(name)[0];
					if (target) {
						scrollTo = $(target).offset().top;
					}
				}

				if (typeof scrollTo == 'number') {
					$(window).scrollTop(scrollTo);
				}

				fire('pjax:success', [
					data,
					status,
					xhr,
					options
				]);
			}
		};

		// Initialize pjax.state for the initial page load. Assume we're
		// using the container and options of the link we're loading for the
		// back button to the initial page. This ensures good back button
		// behavior.
		if (!pjax.state) {
			pjax.state = {
				id       : uniqueId(),
				url      : window.location.href,
				title    : document.title,
				container: options.container,
				fragment : options.fragment,
				timeout  : options.timeout
			};
			window.history.replaceState(pjax.state, document.title);
		}

		// Cancel the current request if we're already pjaxing
		abortXHR(pjax.xhr);

		pjax.options = options;
		var xhr = pjax.xhr = $.ajax(options);

		if (xhr.readyState > 0) {
			if (options.push && !options.replace) {
				// Cache current container element before replacing it
				cachePush(pjax.state.id, [
					options.container,
					cloneContents(context)
				]);

				window.history.pushState(null, '', options.requestUrl);
			}

			fire('pjax:start', [
				xhr,
				options
			]);
			fire('pjax:send', [
				xhr,
				options
			]);
		}

		return pjax.xhr;
	}

	// Public: Reload current page with pjax.
	//
	// Returns whatever $.pjax returns.
	function pjaxReload(container, options) {
		var defaults = {
			url     : window.location.href,
			push    : false,
			replace : true,
			scrollTo: false
		};

		return pjax($.extend(defaults, optionsFor(container, options)));
	}

	// Internal: Hard replace current state with url.
	//
	// Work for around WebKit
	//   https://bugs.webkit.org/show_bug.cgi?id=93506
	//
	// Returns nothing.
	function locationReplace(url) {
		window.history.replaceState(null, '', pjax.state.url);
		window.location.replace(url);
	}

	var initialPop = true;
	var initialURL = window.location.href;
	var initialState = window.history.state;

	// Initialize $.pjax.state if possible
	// Happens when reloading a page and coming forward from a different
	// session history.
	if (initialState && initialState.container) {
		pjax.state = initialState;
	}

	// Non-webkit browsers don't fire an initial popstate event
	if ('state' in window.history) {
		initialPop = false;
	}

	// popstate handler takes care of the back and forward buttons
	//
	// You probably shouldn't use pjax on pages with other pushState
	// stuff yet.
	function onPjaxPopstate(event) {

		// Hitting back or forward should override any pending PJAX request.
		if (!initialPop) {
			abortXHR(pjax.xhr);
		}

		var previousState = pjax.state;
		var state = event.state;
		var direction;

		if (state && state.container) {
			// When coming forward from a separate history session, will get an
			// initial pop with a state we are already at. Skip reloading the current
			// page.
			if (initialPop && initialURL == state.url) {
				return;
			}

			if (previousState) {
				// If popping back to the same state, just skip.
				// Could be clicking back from hashchange rather than a pushState.
				if (previousState.id === state.id) {
					return;
				}

				// Since state IDs always increase, we can deduce the navigation direction
				direction = previousState.id < state.id ? 'forward' : 'back';
			}

			var cache = cacheMapping[state.id] || [];
			var containerSelector = cache[0] || state.container;
			var container = $(containerSelector), contents = cache[1];

			if (container.length) {
				if (previousState) {
					// Cache current container before replacement and inform the
					// cache which direction the history shifted.
					cachePop(direction, previousState.id, [
						containerSelector,
						cloneContents(container)
					]);
				}

				var popstateEvent = $.Event('pjax:popstate', {
					state    : state,
					direction: direction
				});
				container.trigger(popstateEvent);

				var options = {
					id       : state.id,
					url      : state.url,
					container: containerSelector,
					push     : false,
					fragment : state.fragment,
					timeout  : state.timeout,
					scrollTo : false
				};

				if (contents) {
					container.trigger('pjax:start', [
						null,
						options
					]);

					pjax.state = state;
					if (state.title) {
						document.title = state.title;
					}
					var beforeReplaceEvent = $.Event('pjax:beforeReplace', {
						state        : state,
						previousState: previousState
					});
					container.trigger(beforeReplaceEvent, [
						contents,
						options
					]);
					container.html(contents);

					container.trigger('pjax:end', [
						null,
						options
					]);
				} else {
					pjax(options);
				}

				// Force reflow/relayout before the browser tries to restore the
				// scroll position.
				container[0].offsetHeight; // eslint-disable-line no-unused-expressions
			} else {
				locationReplace(location.href);
			}
		}
		initialPop = false;
	}

	// Fallback version of main pjax function for browsers that don't
	// support pushState.
	//
	// Returns nothing since it retriggers a hard form submission.
	function fallbackPjax(options) {
		var url    = typeof options.url === 'function' ? options.url() : options.url,
		    method = options.type ? options.type.toUpperCase() : 'GET';

		var form = $('<form>', {
			method: method === 'GET' ? 'GET' : 'POST',
			action: url,
			style : 'display:none'
		});

		if (method !== 'GET' && method !== 'POST') {
			form.append($('<input>', {
				type : 'hidden',
				name : '_method',
				value: method.toLowerCase()
			}));
		}

		var data = options.data;
		if (typeof data === 'string') {
			$.each(data.split('&'), function(index, value) {
				var pair = value.split('=');
				form.append($('<input>', {
					type : 'hidden',
					name : pair[0],
					value: pair[1]
				}));
			});
		} else if (Array.isArray(data)) {
			$.each(data, function(index, value) {
				form.append($('<input>', {
					type : 'hidden',
					name : value.name,
					value: value.value
				}));
			});
		} else if (typeof data === 'object') {
			var key;
			for (key in data) {
				form.append($('<input>', {
					type : 'hidden',
					name : key,
					value: data[key]
				}));
			}
		}

		$(document.body).append(form);
		form.submit();
	}

	// Internal: Abort an XmlHttpRequest if it hasn't been completed,
	// also removing its event handlers.
	function abortXHR(xhr) {
		if (xhr && xhr.readyState < 4) {
			xhr.onreadystatechange = $.noop;
			xhr.abort();
		}
	}

	// Internal: Generate unique id for state object.
	//
	// Use a timestamp instead of a counter since ids should still be
	// unique across page loads.
	//
	// Returns Number.
	function uniqueId() {
		return (new Date).getTime();
	}

	function cloneContents(container) {
		var cloned = container.clone();
		// Unmark script tags as already being eval'd so they can get executed again
		// when restored from cache. HAXX: Uses jQuery internal method.
		cloned.find('script').each(function() {
			if (!this.src) {
				jQuery._data(this, 'globalEval', false);
			}
		});
		return cloned.contents();
	}

	// Internal: Strip internal query params from parsed URL.
	//
	// Returns sanitized url.href String.
	function stripInternalParams(url) {
		url.search = url.search.replace(/([?&])(_pjax|_)=[^&]*/g, '').replace(/^&/, '');
		return url.href.replace(/\?($|#)/, '$1');
	}

	// Internal: Parse URL components and returns a Locationish object.
	//
	// url - String URL
	//
	// Returns HTMLAnchorElement that acts like Location.
	function parseURL(url) {
		var a = document.createElement('a');
		a.href = url;
		return a;
	}

	// Internal: Return the `href` component of given URL object with the hash
	// portion removed.
	//
	// location - Location or HTMLAnchorElement
	//
	// Returns String
	function stripHash(location) {
		return location.href.replace(/#.*/, '');
	}

	// Internal: Build options Object for arguments.
	//
	// For convenience the first parameter can be either the container or
	// the options object.
	//
	// Examples
	//
	//   optionsFor('#container')
	//   // => {container: '#container'}
	//
	//   optionsFor('#container', {push: true})
	//   // => {container: '#container', push: true}
	//
	//   optionsFor({container: '#container', push: true})
	//   // => {container: '#container', push: true}
	//
	// Returns options Object.
	function optionsFor(container, options) {
		if (container && options) {
			options = $.extend({}, options);
			options.container = container;
			return options;
		} else if ($.isPlainObject(container)) {
			return container;
		} else {
			return {container: container};
		}
	}

	// Internal: Filter and find all elements matching the selector.
	//
	// Where $.fn.find only matches descendants, findAll will test all the
	// top level elements in the jQuery object as well.
	//
	// elems    - jQuery object of Elements
	// selector - String selector to match
	//
	// Returns a jQuery object.
	function findAll(elems, selector) {
		return elems.filter(selector).add(elems.find(selector));
	}

	function parseHTML(html) {
		return $.parseHTML(html, document, true);
	}

	// Internal: Extracts container and metadata from response.
	//
	// 1. Extracts X-PJAX-URL header if set
	// 2. Extracts inline <title> tags
	// 3. Builds response Element and extracts fragment if set
	//
	// data    - String response data
	// xhr     - XHR response
	// options - pjax options Object
	//
	// Returns an Object with url, title, and contents keys.
	function extractContainer(data, xhr, options) {
		var obj = {}, fullDocument = /<html/i.test(data);

		// Prefer X-PJAX-URL header if it was set, otherwise fallback to
		// using the original requested url.
		var serverUrl = xhr.getResponseHeader('X-PJAX-URL');
		obj.url = serverUrl ? stripInternalParams(parseURL(serverUrl)) : options.requestUrl;

		var $head, $body;
		// Attempt to parse response html into elements
		if (fullDocument) {
			$body = $(parseHTML(data.match(/<body[^>]*>([\s\S.]*)<\/body>/i)[0]));
			var head = data.match(/<head[^>]*>([\s\S.]*)<\/head>/i);
			$head = head != null ? $(parseHTML(head[0])) : $body;
		} else {
			$head = $body = $(parseHTML(data));
		}

		// If response data is empty, return fast
		if ($body.length === 0) {
			return obj;
		}

		// If there's a <title> tag in the header, use it as
		// the page's title.
		obj.title = findAll($head, 'title').last().text();

		if (options.fragment) {
			var $fragment = $body;
			// If they specified a fragment, look for it in the response
			// and pull it out.
			if (options.fragment !== 'body') {
				$fragment = findAll($fragment, options.fragment).first();
			}

			if ($fragment.length) {
				obj.contents = options.fragment === 'body' ? $fragment : $fragment.contents();

				// If there's no title, look for data-title and title attributes
				// on the fragment
				if (!obj.title) {
					obj.title = $fragment.attr('title') || $fragment.data('title');
				}
			}

		} else if (!fullDocument) {
			obj.contents = $body;
		}

		// Clean up any <title> tags
		if (obj.contents) {
			// Remove any parent title elements
			obj.contents = obj.contents.not(function() { return $(this).is('title'); });

			// Then scrub any titles from their descendants
			obj.contents.find('title').remove();

			// Gather all script[src] elements
			obj.scripts = findAll(obj.contents, 'script[src]').remove();
			obj.contents = obj.contents.not(obj.scripts);
		}

		// Trim any whitespace off the title
		if (obj.title) {
			obj.title = $.trim(obj.title);
		}

		return obj;
	}

	// Load an execute scripts using standard script request.
	//
	// Avoids jQuery's traditional $.getScript which does a XHR request and
	// globalEval.
	//
	// scripts - jQuery object of script Elements
	//
	// Returns nothing.
	function executeScriptTags(scripts) {
		if (!scripts) {
			return;
		}

		var existingScripts = $('script[src]');

		scripts.each(function() {
			var src = this.src;
			var matchedScripts = existingScripts.filter(function() {
				return this.src === src;
			});
			if (matchedScripts.length) {
				return;
			}

			var script = document.createElement('script');
			var type = $(this).attr('type');
			if (type) {
				script.type = type;
			}
			script.src = $(this).attr('src');
			document.head.appendChild(script);
		});
	}

	// Internal: History DOM caching class.
	var cacheMapping = {};
	var cacheForwardStack = [];
	var cacheBackStack = [];

	// Push previous state id and container contents into the history
	// cache. Should be called in conjunction with `pushState` to save the
	// previous container contents.
	//
	// id    - State ID Number
	// value - DOM Element to cache
	//
	// Returns nothing.
	function cachePush(id, value) {
		cacheMapping[id] = value;
		cacheBackStack.push(id);

		// Remove all entries in forward history stack after pushing a new page.
		trimCacheStack(cacheForwardStack, 0);

		// Trim back history stack to max cache length.
		trimCacheStack(cacheBackStack, pjax.defaults.maxCacheLength);
	}

	// Shifts cache from directional history cache. Should be
	// called on `popstate` with the previous state id and container
	// contents.
	//
	// direction - "forward" or "back" String
	// id        - State ID Number
	// value     - DOM Element to cache
	//
	// Returns nothing.
	function cachePop(direction, id, value) {
		var pushStack, popStack;
		cacheMapping[id] = value;

		if (direction === 'forward') {
			pushStack = cacheBackStack;
			popStack = cacheForwardStack;
		} else {
			pushStack = cacheForwardStack;
			popStack = cacheBackStack;
		}

		pushStack.push(id);
		id = popStack.pop();
		if (id) {
			delete cacheMapping[id];
		}

		// Trim whichever stack we just pushed to to max cache length.
		trimCacheStack(pushStack, pjax.defaults.maxCacheLength);
	}

	// Trim a cache stack (either cacheBackStack or cacheForwardStack) to be no
	// longer than the specified length, deleting cached DOM elements as necessary.
	//
	// stack  - Array of state IDs
	// length - Maximum length to trim to
	//
	// Returns nothing.
	function trimCacheStack(stack, length) {
		while (stack.length > length) {
			delete cacheMapping[stack.shift()];
		}
	}

	// Public: Find version identifier for the initial page load.
	//
	// Returns String version or undefined.
	function findVersion() {
		return $('meta').filter(function() {
			var name = $(this).attr('http-equiv');
			return name && name.toUpperCase() === 'X-PJAX-VERSION';
		}).attr('content');
	}

	// Install pjax functions on $.pjax to enable pushState behavior.
	//
	// Does nothing if already enabled.
	//
	// Examples
	//
	//     $.pjax.enable()
	//
	// Returns nothing.
	function enable() {
		$.fn.pjax = fnPjax;
		$.pjax = pjax;
		$.pjax.enable = $.noop;
		$.pjax.disable = disable;
		$.pjax.click = handleClick;
		$.pjax.submit = handleSubmit;
		$.pjax.reload = pjaxReload;
		$.pjax.defaults = {
			timeout       : 5000,
			push          : true,
			replace       : false,
			type          : 'GET',
			dataType      : 'html',
			scrollTo      : 0,
			maxCacheLength: 20,
			version       : findVersion
		};
		$(window).on('popstate.pjax', onPjaxPopstate);
	}

	// Disable pushState behavior.
	//
	// This is the case when a browser doesn't support pushState. It is
	// sometimes useful to disable pushState for debugging on a modern
	// browser.
	//
	// Examples
	//
	//     $.pjax.disable()
	//
	// Returns nothing.
	function disable() {
		$.fn.pjax = function() { return this; };
		$.pjax = fallbackPjax;
		$.pjax.enable = enable;
		$.pjax.disable = $.noop;
		$.pjax.click = $.noop;
		$.pjax.submit = $.noop;
		$.pjax.reload = function() { window.location.reload(); };

		$(window).off('popstate.pjax', onPjaxPopstate);
	}

	// Add the state property to jQuery's event object so we can use it in
	// $(window).bind('popstate')
	if ($.event.props && $.inArray('state', $.event.props) < 0) {
		$.event.props.push('state');
	} else if (!('state' in $.Event.prototype)) {
		$.event.addProp('state');
	}

	// Is pjax supported by this browser?
	$.support.pjax =
		window.history && window.history.pushState && window.history.replaceState &&
		// pushState isn't reliable on iOS until 5.
		!navigator.userAgent.match(/((iPod|iPhone|iPad).+\bOS\s+[1-4]\D|WebApps\/.+CFNetwork)/)

	if ($.support.pjax) {
		enable()
	} else {
		disable()
	}

})(jQuery);
