selectivizr.js

/*
selectivizr v1.0.3b - (c) Keith Clark, freely distributable under the terms 
of the MIT license.

selectivizr.com
*/
/* 
  
Notes about this source
-----------------------

 * The #DEBUG_START and #DEBUG_END comments are used to mark blocks of code
   that will be removed prior to building a final release version (using a
   pre-compression script)
  
  
References:
-----------
 
 * CSS Syntax          : http://www.w3.org/TR/2003/WD-css3-syntax-20030813/#style
 * Selectors           : http://www.w3.org/TR/css3-selectors/#selectors
 * IE Compatability    : http://msdn.microsoft.com/en-us/library/cc351024(VS.85).aspx
 * W3C Selector Tests  : http://www.w3.org/Style/CSS/Test/CSS3/Selectors/current/html/tests/
 
*/

(function(win) {

	// Determine IE version and stop execution if browser isn't IE. This
	// handles the script being loaded by non IE browsers because the
	// developer didn't use conditional comments.
	var ieUserAgent = navigator.userAgent.match(/MSIE (\d+)/);
	if (!ieUserAgent) {
		return false;
	}

	// =========================== Init Objects ============================

	var doc = document;
	var root = doc.documentElement;
	var xhr = getXHRObject();
	var ieVersion = ieUserAgent[1];

	// If were not in standards mode, IE is too old / new or we can't create
	// an XMLHttpRequest object then we should get out now.
	if (doc.compatMode != 'CSS1Compat' || ieVersion<6 || ieVersion>8 || !xhr) {
		return;
	}
	
	
	// ========================= Common Objects ============================

	// Compatiable selector engines in order of CSS3 support. Note: '*' is
	// a placholder for the object key name. (basically, crude compression)
	var selectorEngines = {
		"NW"								: "*.Dom.select",
		"MooTools"							: "$$",
		"DOMAssistant"						: "*.$", 
		"Prototype"							: "$$",
		"YAHOO"								: "*.util.Selector.query",
		"Sizzle"							: "*", 
		"jQuery"							: "*",
		"dojo"								: "*.query"
	};

	var selectorMethod;
	var enabledWatchers 					= [];     // array of :enabled/:disabled elements to poll
	var domPatches							= [];
	var ie6PatchID 							= 0;      // used to solve ie6's multiple class bug
	var patchIE6MultipleClasses				= true;   // if true adds class bloat to ie6
	var namespace 							= "slvzr";

	// Stylesheet parsing regexp's
	var RE_COMMENT							= /(\/\*[^*]*\*+([^\/][^*]*\*+)*\/)\s*?/g;
	var RE_IMPORT							= /@import\s*(?:(?:(?:url\(\s*(['"]?)(.*)\1)\s*\))|(?:(['"])(.*)\3))\s*([^;]*);/g;
	var RE_ASSET_URL 						= /(behavior\s*?:\s*)?\burl\(\s*(["']?)(?!data:)([^"')]+)\2\s*\)/g;
	var RE_PSEUDO_STRUCTURAL				= /^:(empty|(first|last|only|nth(-last)?)-(child|of-type))$/;
	var RE_PSEUDO_ELEMENTS					= /:(:first-(?:line|letter))/g;
	var RE_SELECTOR_GROUP					= /((?:^|(?:\s*})+)(?:\s*@media[^{]+{)?)\s*([^\{]*?[\[:][^{]+)/g;
	var RE_SELECTOR_PARSE					= /([ +~>])|(:[a-z-]+(?:\(.*?\)+)?)|(\[.*?\])/g; 
	var RE_LIBRARY_INCOMPATIBLE_PSEUDOS		= /(:not\()?:(hover|enabled|disabled|focus|checked|target|active|visited|first-line|first-letter)\)?/g;
	var RE_PATCH_CLASS_NAME_REPLACE			= /[^\w-]/g;
	
	// HTML UI element regexp's
	var RE_INPUT_ELEMENTS					= /^(INPUT|SELECT|TEXTAREA|BUTTON)$/;
	var RE_INPUT_CHECKABLE_TYPES			= /^(checkbox|radio)$/;

	// Broken attribute selector implementations (IE7/8 native [^=""], [$=""] and [*=""])
	var BROKEN_ATTR_IMPLEMENTATIONS			= ieVersion>6 ? /[\$\^*]=(['"])\1/ : null;

	// Whitespace normalization regexp's
	var RE_TIDY_TRAILING_WHITESPACE			= /([(\[+~])\s+/g;
	var RE_TIDY_LEADING_WHITESPACE			= /\s+([)\]+~])/g;
	var RE_TIDY_CONSECUTIVE_WHITESPACE		= /\s+/g;
	var RE_TIDY_TRIM_WHITESPACE				= /^\s*((?:[\S\s]*\S)?)\s*$/;
	
	// String constants
	var EMPTY_STRING						= "";
	var SPACE_STRING						= " ";
	var PLACEHOLDER_STRING					= "$1";

	// =========================== Patching ================================

	// --[ patchStyleSheet() ]----------------------------------------------
	// Scans the passed cssText for selectors that require emulation and
	// creates one or more patches for each matched selector.
	function patchStyleSheet( cssText ) {
		return cssText.replace(RE_PSEUDO_ELEMENTS, PLACEHOLDER_STRING).
			replace(RE_SELECTOR_GROUP, function(m, prefix, selectorText) {	
    			var selectorGroups = selectorText.split(",");
    			for (var c = 0, cs = selectorGroups.length; c < cs; c++) {
    				var selector = normalizeSelectorWhitespace(selectorGroups[c]) + SPACE_STRING;
    				var patches = [];
    				selectorGroups[c] = selector.replace(RE_SELECTOR_PARSE, 
    					function(match, combinator, pseudo, attribute, index) {
    						if (combinator) {
    							if (patches.length>0) {
    								domPatches.push( { selector: selector.substring(0, index), patches: patches } )
    								patches = [];
    							}
    							return combinator;
    						}		
    						else {
    							var patch = (pseudo) ? patchPseudoClass( pseudo ) : patchAttribute( attribute );
    							if (patch) {
    								patches.push(patch);
    								return "." + patch.className;
    							}
    							return match;
    						}
    					}
    				);
    			}
    			return prefix + selectorGroups.join(",");
    		});
	};

	// --[ patchAttribute() ]-----------------------------------------------
	// returns a patch for an attribute selector.
	function patchAttribute( attr ) {
		return (!BROKEN_ATTR_IMPLEMENTATIONS || BROKEN_ATTR_IMPLEMENTATIONS.test(attr)) ? 
			{ className: createClassName(attr), applyClass: true } : null;
	};

	// --[ patchPseudoClass() ]---------------------------------------------
	// returns a patch for a pseudo-class
	function patchPseudoClass( pseudo ) {

		var applyClass = true;
		var className = createClassName(pseudo.slice(1));
		var isNegated = pseudo.substring(0, 5) == ":not(";
		var activateEventName;
		var deactivateEventName;

		// if negated, remove :not() 
		if (isNegated) {
			pseudo = pseudo.slice(5, -1);
		}
		
		// bracket contents are irrelevant - remove them
		var bracketIndex = pseudo.indexOf("(")
		if (bracketIndex > -1) {
			pseudo = pseudo.substring(0, bracketIndex);
		}		
		
		// check we're still dealing with a pseudo-class
		if (pseudo.charAt(0) == ":") {
			switch (pseudo.slice(1)) {

				case "root":
					applyClass = function(e) {
						return isNegated ? e != root : e == root;
					}
					break;

				case "target":
					// :target is only supported in IE8
					if (ieVersion == 8) {
						applyClass = function(e) {
							var handler = function() { 
								var hash = location.hash;
								var hashID = hash.slice(1);
								return isNegated ? (hash == EMPTY_STRING || e.id != hashID) : (hash != EMPTY_STRING && e.id == hashID);
							};
							addEvent( win, "hashchange", function() {
								toggleElementClass(e, className, handler());
							})
							return handler();
						}
						break;
					}
					return false;
				
				case "checked":
					applyClass = function(e) { 
						if (RE_INPUT_CHECKABLE_TYPES.test(e.type)) {
							addEvent( e, "propertychange", function() {
								if (event.propertyName == "checked") {
									toggleElementClass( e, className, e.checked !== isNegated );
								} 							
							})
						}
						return e.checked !== isNegated;
					}
					break;
					
				case "disabled":
					isNegated = !isNegated;

				case "enabled":
					applyClass = function(e) { 
						if (RE_INPUT_ELEMENTS.test(e.tagName)) {
							addEvent( e, "propertychange", function() {
								if (event.propertyName == "$disabled") {
									toggleElementClass( e, className, e.$disabled === isNegated );
								} 
							});
							enabledWatchers.push(e);
							e.$disabled = e.disabled;
							return e.disabled === isNegated;
						}
						return pseudo == ":enabled" ? isNegated : !isNegated;
					}
					break;
					
				case "focus":
					activateEventName = "focus";
					deactivateEventName = "blur";
								
				case "hover":
					if (!activateEventName) {
						activateEventName = "mouseenter";
						deactivateEventName = "mouseleave";
					}
					applyClass = function(e) {
						addEvent( e, isNegated ? deactivateEventName : activateEventName, function() {
							toggleElementClass( e, className, true );
						})
						addEvent( e, isNegated ? activateEventName : deactivateEventName, function() {
							toggleElementClass( e, className, false );
						})
						return isNegated;
					}
					break;
					
				// everything else
				default:
					// If we don't support this pseudo-class don't create 
					// a patch for it
					if (!RE_PSEUDO_STRUCTURAL.test(pseudo)) {
						return false;
					}
					break;
			}
		}
		return { className: className, applyClass: applyClass };
	};

	// --[ applyPatches() ]-------------------------------------------------
	function applyPatches() {
		var elms, selectorText, patches, domSelectorText;

		for (var c=0; c<domPatches.length; c++) {

			(function(){

				var iterator = c;
				
				setTimeout(function(){

					selectorText = domPatches[iterator].selector;
					patches = domPatches[iterator].patches;

					// Although some selector libraries can find :checked :enabled etc.
					// we need to find all elements that could have that state because
					// it can be changed by the user.
					domSelectorText = selectorText.replace(RE_LIBRARY_INCOMPATIBLE_PSEUDOS, EMPTY_STRING);

					// If the dom selector equates to an empty string or ends with
					// whitespace then we need to append a universal selector (*) to it.
					if (domSelectorText == EMPTY_STRING || domSelectorText.charAt(domSelectorText.length - 1) == SPACE_STRING) {
						domSelectorText += "*";
					}

					// Ensure we catch errors from the selector library
					try {
						elms = selectorMethod( domSelectorText );
					} catch (ex) {
						// #DEBUG_START
						log( "Selector '" + selectorText + "' threw exception '" + ex + "'" );
						// #DEBUG_END
					}


					if (elms) {
						for (var d = 0, dl = elms.length; d < dl; d++) {
							var elm = elms[d];
							var cssClasses = elm.className;
							for (var f = 0, fl = patches.length; f < fl; f++) {
								var patch = patches[f];
								if (!hasPatch(elm, patch)) {
									if (patch.applyClass && (patch.applyClass === true || patch.applyClass(elm) === true)) {
										cssClasses = toggleClass(cssClasses, patch.className, true );
									}
								}
							}
							elm.className = cssClasses;
						}
					}
				}, 0);
			})();
		}
	};

	// --[ hasPatch() ]-----------------------------------------------------
	// checks for the exsistence of a patch on an element
	function hasPatch( elm, patch ) {
		return new RegExp("(^|\\s)" + patch.className + "(\\s|$)").test(elm.className);
	};
	
	
	// =========================== Utility =================================
	
	function createClassName( className ) {
		return namespace + "-" + ((ieVersion == 6 && patchIE6MultipleClasses) ?
			ie6PatchID++
		:
			className.replace(RE_PATCH_CLASS_NAME_REPLACE, function(a) { return a.charCodeAt(0) }));
	};

	// --[ log() ]----------------------------------------------------------
	// #DEBUG_START
	function log( message ) {
		if (win.console) {
			win.console.log(message);
		}
	};
	// #DEBUG_END

	// --[ trim() ]---------------------------------------------------------
	// removes leading, trailing whitespace from a string
	function trim( text ) {
		return text.replace(RE_TIDY_TRIM_WHITESPACE, PLACEHOLDER_STRING);
	};

	// --[ normalizeWhitespace() ]------------------------------------------
	// removes leading, trailing and consecutive whitespace from a string
	function normalizeWhitespace( text ) {
		return trim(text).replace(RE_TIDY_CONSECUTIVE_WHITESPACE, SPACE_STRING);
	};

	// --[ normalizeSelectorWhitespace() ]----------------------------------
	// tidies whitespace around selector brackets and combinators
	function normalizeSelectorWhitespace( selectorText ) {
		return normalizeWhitespace(selectorText.
			replace(RE_TIDY_TRAILING_WHITESPACE, PLACEHOLDER_STRING).
			replace(RE_TIDY_LEADING_WHITESPACE, PLACEHOLDER_STRING)
		);
	};

	// --[ toggleElementClass() ]-------------------------------------------
	// toggles a single className on an element
	function toggleElementClass( elm, className, on ) {
		var oldClassName = elm.className;
		var newClassName = toggleClass(oldClassName, className, on);
		if (newClassName != oldClassName) {
			elm.className = newClassName;
			elm.parentNode.className += EMPTY_STRING;
		}
	};

	// --[ toggleClass() ]--------------------------------------------------
	// adds / removes a className from a string of classNames. Used to 
	// manage multiple class changes without forcing a DOM redraw
	function toggleClass( classList, className, on ) {
		var re = RegExp("(^|\\s)" + className + "(\\s|$)");
		var classExists = re.test(classList);
		if (on) {
			return classExists ? classList : classList + SPACE_STRING + className;
		} else {
			return classExists ? trim(classList.replace(re, PLACEHOLDER_STRING)) : classList;
		}
	};
	
	// --[ addEvent() ]-----------------------------------------------------
	function addEvent(elm, eventName, eventHandler) {
		elm.attachEvent("on" + eventName, eventHandler);
	};

	// --[ getXHRObject() ]-------------------------------------------------
	function getXHRObject() {
		if (win.XMLHttpRequest) {
			return new XMLHttpRequest;
		}
		try	{ 
			return new ActiveXObject('Microsoft.XMLHTTP');
		} catch(e) { 
			return null;
		}
	};

	// --[ loadStyleSheet() ]-----------------------------------------------
	function loadStyleSheet( url ) {
		xhr.open("GET", url, false);
		xhr.send();
		return (xhr.status==200) ? xhr.responseText : EMPTY_STRING;	
	};
	
	// --[ resolveUrl() ]---------------------------------------------------
	// Converts a URL fragment to a fully qualified URL using the specified
	// context URL. Returns null if same-origin policy is broken
	function resolveUrl( url, contextUrl, ignoreSameOriginPolicy ) {

		function getProtocol( url ) {
			return url.substring(0, url.indexOf("//"));
		};

		function getProtocolAndHost( url ) {
			return url.substring(0, url.indexOf("/", 8));
		};

		if (!contextUrl) {
			contextUrl = baseUrl;
		}

		// protocol-relative path
		if (url.substring(0,2)=="//") {
			url = getProtocol(contextUrl) + url;
		}

		// absolute path
		if (/^https?:\/\//i.test(url)) {
			return !ignoreSameOriginPolicy && getProtocolAndHost(contextUrl) != getProtocolAndHost(url) ? null : url ;
		}

		// root-relative path
		if (url.charAt(0)=="/")	{
			return getProtocolAndHost(contextUrl) + url;
		}

		// relative path
		var contextUrlPath = contextUrl.split(/[?#]/)[0]; // ignore query string in the contextUrl	
		if (url.charAt(0) != "?" && contextUrlPath.charAt(contextUrlPath.length - 1) != "/") {
			contextUrlPath = contextUrlPath.substring(0, contextUrlPath.lastIndexOf("/") + 1);
		}

		return contextUrlPath + url;
	};
	
	// --[ parseStyleSheet() ]----------------------------------------------
	// Downloads the stylesheet specified by the URL, removes it's comments
	// and recursivly replaces @import rules with their contents, ultimately
	// returning the full cssText.
	function parseStyleSheet( url ) {
		if (url) {
			return loadStyleSheet(url).replace(RE_COMMENT, EMPTY_STRING).
			replace(RE_IMPORT, function( match, quoteChar, importUrl, quoteChar2, importUrl2, media ) {
				var cssText = parseStyleSheet(resolveUrl(importUrl || importUrl2, url));
				return (media) ? "@media " + media + " {" + cssText + "}" : cssText;
			}).
			replace(RE_ASSET_URL, function( match, isBehavior, quoteChar, assetUrl ) { 
				quoteChar = quoteChar || EMPTY_STRING;
				return isBehavior ? match : " url(" + quoteChar + resolveUrl(assetUrl, url, true) + quoteChar + ") "; 
			});
		}
		return EMPTY_STRING;
	};

	// --[ getStyleSheets() ]-----------------------------------------------
	function getStyleSheets() {
		var url, stylesheet;
		for (var c = 0; c < doc.styleSheets.length; c++) {
			stylesheet = doc.styleSheets[c];
			if (stylesheet.href != EMPTY_STRING) {
				url = resolveUrl(stylesheet.href);
				if (url) {
					stylesheet.cssText = stylesheet["rawCssText"] = patchStyleSheet( parseStyleSheet( url ) );
				}
			}
		}
	};

	// --[ init() ]---------------------------------------------------------
	function init() {
		applyPatches();

		// :enabled & :disabled polling script (since we can't hook 
		// onpropertychange event when an element is disabled) 
		if (enabledWatchers.length > 0) {
			setInterval( function() {
				for (var c = 0, cl = enabledWatchers.length; c < cl; c++) {
					var e = enabledWatchers[c];
					if (e.disabled !== e.$disabled) {
						if (e.disabled) {
							e.disabled = false;
							e.$disabled = true;
							e.disabled = true;
						}
						else {
							e.$disabled = e.disabled;
						}
					}
				}
			}, 250)
		}
	};

	// Determine the baseUrl and download the stylesheets
	var baseTags = doc.getElementsByTagName("BASE");
	var baseUrl = (baseTags.length > 0) ? baseTags[0].href : doc.location.href;
	getStyleSheets();

	// Bind selectivizr to the ContentLoaded event. 
	ContentLoaded(win, function() {
		// Determine the "best fit" selector engine
		for (var engine in selectorEngines) {
			var members, member, context = win;
			if (win[engine]) {
				members = selectorEngines[engine].replace("*", engine).split(".");
				while ((member = members.shift()) && (context = context[member])) {}
				if (typeof context == "function") {
					selectorMethod = context;
					init();
					return;
				}
			}
		}
	});
	

	
	/*!
	 * ContentLoaded.js by Diego Perini, modified for IE<9 only (to save space)
	 *
	 * Author: Diego Perini (diego.perini at gmail.com)
	 * Summary: cross-browser wrapper for DOMContentLoaded
	 * Updated: 20101020
	 * License: MIT
	 * Version: 1.2
	 *
	 * URL:
	 * http://javascript.nwbox.com/ContentLoaded/
	 * http://javascript.nwbox.com/ContentLoaded/MIT-LICENSE
	 *
	 */

	// @w window reference
	// @f function reference
	function ContentLoaded(win, fn) {

		var done = false, top = true,
		init = function(e) {
			if (e.type == "readystatechange" && doc.readyState != "complete") return;
			(e.type == "load" ? win : doc).detachEvent("on" + e.type, init, false);
			if (!done && (done = true)) fn.call(win, e.type || e);
		},
		poll = function() {
			try { root.doScroll("left"); } catch(e) { setTimeout(poll, 50); return; }
			init('poll');
		};

		if (doc.readyState == "complete") fn.call(win, EMPTY_STRING);
		else {
			if (doc.createEventObject && root.doScroll) {
				try { top = !win.frameElement; } catch(e) { }
				if (top) poll();
			}
			addEvent(doc,"readystatechange", init);
			addEvent(win,"load", init);
		}
	};
})(this);