深入学习jquery源码之jQuery的选择器引擎Sizzle
Sizzle是一个纯javascript CSS选择器引擎。jquery1.3开始使用sizzle，Sizzle一反传统采取了相反的Right To Left的查询匹配方式,效率提高.Sizzle是jQuery作者John Resig新写的DOM选择器引擎,速度号称业界第一.Sizzle完全独立于jQuery，若不想用jQuery,你可只用Sizzle实现,压缩3K多http://url.cn/J73IkN
一般选择器的匹配模式（包括jq1.2之前），都是一个顺序的思维方式，在需要递进式匹配时，比如$(‘div span’) 这样的匹配时，执行的操作都是先匹配页面中div然后再匹配它的节点下的span标签，之后返回结果。
Sizzle则采取了相反Right To Left的实现方式，先搜寻页面中所有的span标签，再其后的操作中才去判断它的父节点（包括父节点以上）是否为div，是则压入数组，否则pass，进入下一判断，最后返回该操作序列。
当我们给$符传递进一个参数（也可能是多个）时，此时它会根据参数的类型（domElement | string | fn | array）进入不同的流程，在此，重点看 string 类型的处理，因为只有它才可以触发Sizzle。首先调用正则匹配看是否为创建dom节点的操作，然后看是否为简单id匹配，这一步也由正则匹配完成，否则进入jQuery.fn.find()函数，由此进入Sizzle的天地。
当进入Sizzle时，一般情况下会配备三参：所要匹配的选择符，上下文，匹配的结果集。调用正则对传入的selector做一次”预匹配”.
var chunker = /((?:\((?:\([^()]+\)|[^()]+)+\)|\[(?:\[[^[\]]*\]|['"][^'"]*['"]|[^[\]'"]+)+\]|\\.|[^ >+~,(\[\\]+)+|[>+~])(\s*,\s*)?/g,
让我们看一下一个简单选择器的实现过程：比如 div > p。我们要先找出符合条件的div[div]，再找出符合条件的p[p]，最后在上下文里[div]过滤出符合条件”>”的p[p];抽象一点的说法就是：在已知的上下文里，根据关系找出相应的节点。他们靠关系联系起来。那么对于选择器的操作也就是根据关系来分组。一次次缩小上下文，直到找出符合条件的节点。
回到我们的话题，还是先看看这个令人费解的正则，相信你会有更好的分析方法，但是眼下，我还是一点点的拆分，让它表达的更清晰一点。先按照分组拆，即():
((?:\((?:\([^()]+\)|[^()]+)+\)|\[(?:\[[^\[\]]*\]|['"][^'"]*['"]|[^\[\]'"]+)+\]|\\.|[^ >+~,(\[\\]+)+|[>+~])
(\s*,\s*)?
((?:.|\r|\n)*)
第一行还是有点长，用’|'拆分它:
1. (?:\((?:\([^()]+\)
2.[^()]+)+\)
3. \[(?:\[[^[\]]*\]
4. [^[\]]+)+\]|\\.
5.[^ >+~,(\[]+)+
6.[>+~]
对于如div > p。会得到数组结果['div','>','p']。
对于更复杂的选择器，如div.classname > p.classname。会得到结果['div.classname','>','p.classname']。
对于具有合并的‘,’,只是递归调用下获取结果再合并而已。过程开始变得简单起来。
对于普通的解析过程，我们遵循着从左到右的顺序即可完成我们的目标。
让我们总结下步骤：
1.先查找页面上所有的div
2.循环所有的div，查找每个div下的p
3.合并结果
Sizzle用了截然相反的步骤：
1.先查找页面上所有的p
2.循环所有的p，查找每个p的父元素
1.如果不是div，遍历上一层。
2.如果已经是顶层，排除此p。
3.如果是div，则保存此p元素。
由子元素来查找父元素，能得到更好的效率。看，打破常规思维后不仅步骤更简单了，而且效率上也得到了些许提升。
所有的选择器都可以这样解析吗？不是，采用right -> left的顺序是有前提条件的：没有位置关系的约束。
比如如下这段html：
<div> <p id="p1">p1content <p id="p2">p2content </div> <div> <p id="p3">p3content <p id="p4">p4content </div>对于选择器：$(“div p:first”)只会返回["#p1"]
而$(“div p:first-child”)则返回["#p1", "#p3"]
两者的区别在于位置filter的结果依赖于它前面的selector解析的结果，而其它 filter，只依赖于当前元素本身，就可以判断它是否满足filter。
那Sizzle是通过什么来判定进入哪一个流程呢，答案是origPOS的正则匹配,origPos指向了Expr中match对象的POS属性,而POS中存储了五花八门的位置类约束，如下：
/:(nth|eq|gt|lt|first|last|even|odd)(?:\((\d*)\))?(?=[^-]|$)/ //POS的值
这样一来，第一步的流程判断就已明朗。
当处于1的情况时:
首先根据需要对当前处理的A数组元素进行一系列修正操作（Expr.relative主刀）。然后调用posProcess函数对修复后的元素进行匹配.
其中，还需一层判断，如果有层级约束，eg ‘>,’:input’ 会转化为 ‘> :input’,因为在最初调用chunker进行预匹配的时候，这些是会被分割为单个数组元素的，但在这里需要将它们做一次合并，这是由posProcess所处理的数据格式所决定的
源码片段a: — posProcess函数匹配核心
//如果存在伪类选择符，从selector中移除，并保存在later中 // 这样一来，匹配对象便分离出来：selector（简单选择符存储器）和later（伪类选择符存储器）。 while ( (match = Expr.match.PSEUDO.exec( selector )) ) { later += match[0]; selector = selector.replace( Expr.match.PSEUDO, "" ); } //构造selector，并调用Sizzle进行匹配,将结果存储在tmpSet中 selector = Expr.relative[selector] ? selector + "*" : selector; for ( var i = 0, l = root.length; i < l; i++ ) { Sizzle( selector, root[i], tmpSet ); } // 最后便是filter的过滤 return Sizzle.filter( later, tmpSet );
源码片段b: — 对预匹配后的数组A中元素的处理
//这个为特例，被正则分割的A数组长度为2，则合并数组元素，上下文则原封不动为Sizzle传递进来的context。 if ( parts.length === 2 && Expr.relative[ parts[0] ] ) { // 完成一次匹配， 由posProcess 内部调用 filter进行匹配 // 但在匹配前，完成了一次连接选择符的操作 // 存入set，注 set 当前还不是最终的结果，其这里的set和上面的tmpSet一样，都是一个"暂时性"的结果集 set = posProcess( parts[0] + parts[1], context );
源码片段c: — 如果存在位置约束关系， 正向匹配。
set = Expr.relative[ parts[0] ] ? [ context ] : // 否则对队列首元素进行一次简单匹配操作 Sizzle( parts.shift(), context );
分析Expr.relative，可以看出，它包含了4种dom元素间关系的判断，分别是 “+”, “>”, “”, “~”
每一轮的匹配，都会先判断A数组的首元素是不是代表tag间关系符(+,>等) ，而做后续处理.同时对A数组进行循环，依次做类似的处理
源码片段d — 对A数组(parts)的循环处理及后续
while ( parts.length ) { // 依次对 所匹配到的 数组中元素进行 递进匹配 selector = parts.shift(); // '>' -> '>input' 的形式 if ( Expr.relative[ selector ] ) selector += parts.shift(); set = posProcess( selector, set );
当处于2的情况时:
就有着不同之处,先看小片代码
源码片段e: — 根据当前流程设置ret(两种情况)
//为ret绑定正确的返回值 var ret = seed ? //seed 为上一次调用sizzle返回值， 即前文中提到的set|tmpset //将预匹配后的A数组(parts)中的最后元素设置为ret的expr属性，set属性设为上一次匹配的结果集。 { expr: parts.pop(), set: makeArray(seed) } : //如果是第一次调用，则进行匹配操作,调用find函数 // 以parts数组最末元素为当前选择符，进行匹配操作，同时设置与之相关的context Sizzle.find( parts.pop(), parts.length === 1 && context.parentNode ? context.parentNode : context, isXML(context) );
2的情况为一般逻辑处理，从这小段代码便可得到Sizzle的匹配机制，每一次的调用都以数组末元素为基准，以上一次（或预设context）为上下文约束关系以右到左的匹配,最后返回匹配结果。结合了DOM结构的特性，性能上也得到了大幅的提升。
我们知道选择器的类型是有效率差别的，id选择器效率最高，其次是class、name、tag、最后是最差的*表达式。在Sizzle.find函数中，会按照这个效率的顺序查找元素，如果没有id就找class，依次下去。当然，class的支持需要方法getElementsByClassName。如果没有，就只好从id跳到name。
if ( document.getElementsByClassName && document.documentElement.getElementsByClassName ) (function(){ // ... // 如果支持直接获取，则将获取class的方法 直接添加进 Expr.order中 ['ID', 'NAME', 'TAG'] Expr.order.splice(1, 0, "CLASS"); //同时在find中追加对class的获取 Expr.find.CLASS = function(match, context, isXML) { if ( typeof context.getElementsByClassName !== "undefined" && !isXML ) { return context.getElementsByClassName(match[1]); } }; })();
在Sizzle.find函数中，做了一系列的逻辑判断，来保证返回结果的正确性，首先在进入find时，保证了expr不为空的，然后根据表达式类型(id|name|tag|class?)来选择与之对应的匹配分支进行实现，最后再做适当的收尾工作，将返回结果定义为对象，来移交给filter,完成整个流程。
源码片段f: — find 函数核心
//order: [ "ID", "NAME", "TAG" ] // 当然，如果浏览器支持对class的直接获取时，order中就会出现class的相关匹配规则 for ( var i = 0, l = Expr.order.length; i < l; i++ ) { var type = Expr.order[i], match; // 根据 type 对所传进来的expr 进行正则匹配 // match中通过正则限制了这三类匹配方式的条件。 // 1. ID: /#((?:[\w\u00c0-\uFFFF_-]|\\.)+)/, // 2. NAME: /
name=[′"]∗((?:[\w\u00c0−\uFFFF−]|.)+)[′"]∗
name=[′"]∗((?:[\w\u00c0−\uFFFF−]|.)+)[′"]∗
/, // 3. TAG: /^((?:[\w\u00c0-\uFFFF\*_-]|\\.)+)/, if ( (match = Expr.match[ type ].exec( expr )) ) { var left = RegExp.leftContext; //保证返回结果的正确性，如果存在\，则删除 if ( left.substr( left.length - 1 ) !== "\\" ) { match[1] = (match[1] || "").replace(/\\/g, ""); // 根据type调用 sizzle.selector.find方法获取结果集。 set = Expr.find[ type ]( match, context, isXML ); if ( set != null ) { //如果匹配成功，删除已经匹配的expr expr = expr.replace( Expr.match[ type ], "" ); break; } } } } return {set: set, expr: expr}; };
在所返回的对象中，expr的作用便是为了辅佐filter这把大器所需要完成任务的工具,到此就可以调用Sizzle.filter对ret.set再做一次精确匹配(匹配规则即ret.expr),以及tag间的位置约束关系的匹配（这部分同1中类似）.
源码片段g: — 和源码片段d有类似之处。不作详述
while ( parts.length ) { var cur = parts.pop(), pop = cur; // 是否存在 类似这样的匹配 eg: '+', '>'等 if ( !Expr.relative[ cur ] ) { cur = ""; } else { //如果存在层间关系的约束 则修复 cur 和pop的指向 // eg ['div', '+', 'span'] => pop = div; cur = '+'; 并进入 relative的匹配。 pop = parts.pop(); } // 确保拥有上下文 代码略过 Expr.relative[ cur ]( checkSet, pop, isXML(context) ); }
之后便接近sizzle尾声：结果集的处理(将所匹配的结果set 追加进 result中)。当然，如果有多表达式,便会再一次调用。
源码解析
以’div > span p span:last’这个选择符为例，看看它的调用链是如何顺次完成的。
根据对源码的剖析，理解如下：
jquery.init -> jquery.prototype.find
进入Sizzle(对xml的判断) -> 设置parts数组等在匹配中所需要的元素 -> 根据数组长度以及调用origPos进行判断，来决定进入哪个分支，在这个实例下进入分支1
循环调用Sizzle进行匹配，将结果存入set中(因为在这一过程中是循环调用，所以对Sizzle的判断也是需要多次，进入哪一分支当然也会是不一样的，比如第二轮循环判断则进入分支2中进行处理) ,对于>号的处理，也会将它合并在其后的span中，构成新的选择符 ‘>span’,然后进入Expr.relative进行匹配，同时调用posProcess。
调用Sizzle.find 匹配除伪类以外的部分(即这里的选择器不包含:last),首先会调用Expr.find的find方法来判断是否为哪一类匹配，在这一实例中，为TAG匹配。
对从4步中生成的对象进行过滤,匹配’>'(这一步的匹配是由Sizzle.filter触发，由Expr.relative完成),而在匹配’span:last’时则由posProcess来触发，设置later值(:first)以及selector(span)，对span的匹配和4步骤一样，重复匹配，而对:first的匹配则是第5步的重头戏，也就是调用Sizzle.filter来完成, 由此便生成了最后的匹配结果。
对于有‘,’这样需要合并的选择器，Sizzle在获取结果后会按照文档流进行排序。所以，你可能会遇到这样的问题：把一个结果集append到新的节点后，新的节点可能不会按照你书写的选择器的顺序出现。
以上，可以得出以下结论：大致通过如下步骤来完成：
1.对表达式分组。
2.选择合适的处理顺序。
3.在当前的上下文里过滤要找的节点。并更新上下文。重复这一过程，直到结尾。
4.对结果排序，如果需要的话。
5.返回结果数组。
前向兼容
querySelectorAll
其实不止这一处，在Sizzle的API手册中Internal部分的find 函数（与filter构成了Sizzle的两把宝剑），在传递进该方法的参数可以用querySelectorAll() （依赖于当前的浏览器执行环境） 直接获取时，它则直接调用该方法，既拥有了向前兼容的特性，又达到了速度的提升。
虽然有些环境实现了方法querySelectorAll，但是会有bug。
//如果当前document 支持 querySelectorAll方法,则将浏览器可以完成的匹配完全交给浏览器 if ( document.querySelectorAll ) (function(){ var oldSizzle = Sizzle; // 解决Safari bug 略过 ... Sizzle = function(query, context, extra, seed){ context = context || document; // 因为querySelectorAll 在domElement 节点上操作时，存在bug 所以多了这样的判断 // bug info: http://ejohn.org/blog/thoughts-on-queryselectorall/ if ( !seed && context.nodeType === 9 && !isXML(context) ) { return makeArray( context.querySelectorAll(query), extra ); } // querySelectorAll 可用则直接返回结果，否则才调用 sizzle return oldSizzle(query, context, extra, seed); }; // oldSizzle 方法追加进 新的 Sizzle 中 })();
对于任何一个开发者，我想，若浏览器原生已提供了实现方法，他都不会去高效而求繁琐吧。这一点在Sizzle中得到了充分的体现，总是尽可能的使用相应环境下已实现的原生方法。所以在IE的低版本中(比如IE6)Sizzle的表现更加出众，在高级的浏览器中的对比却没有那么大的差别。
扩展
如何定义自己的选择器呢.如果项目中频繁使用某些过滤规则，是不是把它作为一个选择器更有效呢。
既然javascript的对象可以任意扩充，只要我们访问得到，那么我们就可以很轻松得创建出自己的选择器
在jQuery.expr.filter对象中，有很多内置的选择器，比如 ‘disabled’,'text’,那我们就扩充它,比如，想寻找包含span的div元素
// filter的简写 ':' jQuery.expr[":"] = jQuery.expr.filters; $.extend($.expr[':'], { hasSpan: function(e) { return $(e).find('span').length > 0; } });
这样，我们就拥有了 ‘:hasSpan’ 的选择器，使用当然和默认的一样。
//直接用就可以了 $('div:hasSpan')....
比较
再拾YUI3，在经过大幅度变化，以全新姿态出现，从选择器上的执行上效率不逊色于Sizzle几毫，初看YUI时就一直对它的模块细粒度化赞不绝口，但是从如我这样的实用主义者的角度来看，选择器就应该是一个单独的模块，就如同jQuery分离而出的Sizzle。但在YUI term眼里，为了让代码的组织结构看上去更加的理想化，更加具有”YUI3“的特色，将之在代码结构上又细分出一二三，比起Sizzle的简洁，它显得太过学院派。
除此，在选择器的扩展上，sizzle表现胜于YUI3 selector，在实现css1~css3选择器的基础上，又对常用的功能进行了扩展。比如对表单元素快捷操作。据我所知，开发者对这类型选择器的使用频率并不是想象中那么低。既然有了模块的细分，为什么不将这部分作为一个可扩充性的功能点模块融入框架中呢。Sizzle于开发者就如同一块可口味佳的点心，满足我们各式各样的胃口，简洁，不失其功能的强劲，这点非常值得称道。
总得来看，Sizzle与YUI就好象一个面向实际与理想主义的比较。这里没有对错之分，从不同角度来看，都能略窥其各自的禅意。前者从如何为开发者带来便利的角度考虑，让开发者实时觉得它的简单可信赖。后者，也寄托了自己对web的构想，如果浏览器原生全部支持css3-selector，那岂不是完全不用引入该模块了，不过我想，真到那时候，各框架也都会有很大的变化了，只是我对这一天的到来抱有比较消极的态度，这是后话。
总结
本文从总体上讨论了jQuery之Sizzle选择器的实现原理，通过一个初步的流程分析，让各位读者对此有一个大致印象，毫无疑问，更深层次的匹配，也只是它的递归调用，再匹配而已。
这里，没有做与其他框架在效率上的比较，如果你还对它的效率还有所怀疑的话，你可以自行比较。
如果你感兴趣，更推荐你继续去探索在1.4中着重优化的api源码，或许，会给你更多的启示
思考
从jQuery的角度来讲，Sizzle的出现随之也带来了web上的一些新的局面，在追求效率的同时，即使是这类单种子模式的库也是需要将之分离开来，来设计成能够独立使用，独立维护的引擎。
从选择器的角度来讲，Sizzle这次算法的提升，我初步的结论是它结合了DOM这一特定的数据结构，使其每次的匹配能够更精准,以此获得引擎效率上的提升。
我们可否多想想，在思维的开拓上能给我们留下多少财富。很多问题的解决，在换一种新的思维方式后，是不是常常会有柳暗花明的感觉呢。
jquery源码
jQuery.find = Sizzle;
jQuery.expr = Sizzle.selectors;
jQuery.expr[":"] = jQuery.expr.pseudos;
jQuery.unique = Sizzle.uniqueSort;
jQuery.text = Sizzle.getText;
jQuery.isXMLDoc = Sizzle.isXML;
jQuery.contains = Sizzle.contains;
var Sizzle =
/*!
* Sizzle CSS Selector Engine v2.2.0-pre
* http://sizzlejs.com/
*
* Copyright 2008, 2014 jQuery Foundation, Inc. and other contributors
* Released under the MIT license
* http://jquery.org/license
*
* Date: 2014-12-16
*/
(function (window) {
var i,
support,
Expr,
getText,
isXML,
tokenize,
compile,
select,
outermostContext,
sortInput,
hasDuplicate,
// Local document vars
setDocument,
document,
docElem,
documentIsHTML,
rbuggyQSA,
rbuggyMatches,
matches,
contains,
// Instance-specific data
expando = "sizzle" + 1 * new Date(),
preferredDoc = window.document,
dirruns = 0,
done = 0,
classCache = createCache(),
tokenCache = createCache(),
compilerCache = createCache(),
sortOrder = function (a, b) {
if (a === b) {
hasDuplicate = true;
}
return 0;
},
// General-purpose constants
MAX_NEGATIVE = 1 << 31,
// Instance methods
hasOwn = ({}).hasOwnProperty,
arr = [],
pop = arr.pop,
push_native = arr.push,
push = arr.push,
slice = arr.slice,
// Use a stripped-down indexOf as it's faster than native
// http://jsperf.com/thor-indexof-vs-for/5
indexOf = function (list, elem) {
var i = 0,
len = list.length;
for (; i < len; i++) {
if (list[i] === elem) {
return i;
}
}
return -1;
},
booleans = "checked|selected|async|autofocus|autoplay|controls|defer|disabled|hidden|ismap|loop|multiple|open|readonly|required|scoped",
// Regular expressions
// Whitespace characters http://www.w3.org/TR/css3-selectors/#whitespace
whitespace = "[\\x20\\t\\r\\n\\f]",
// http://www.w3.org/TR/css3-syntax/#characters
characterEncoding = "(?:\\\\.|[\\w-]|[^\\x00-\\xa0])+",
// Loosely modeled on CSS identifier characters
// An unquoted value should be a CSS identifier http://www.w3.org/TR/css3-selectors/#attribute-selectors
// Proper syntax: http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier
identifier = characterEncoding.replace("w", "w#"),
// Attribute selectors: http://www.w3.org/TR/selectors/#attribute-selectors
attributes = "\\[" + whitespace + "*(" + characterEncoding + ")(?:" + whitespace +
// Operator (capture 2)
"*([*^$|!~]?=)" + whitespace +
// "Attribute values must be CSS identifiers [capture 5] or strings [capture 3 or capture 4]"
"*(?:'((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\"|(" + identifier + "))|)" + whitespace +
"*\\]",
pseudos = ":(" + characterEncoding + ")(?:\\((" +
// To reduce the number of selectors needing tokenize in the preFilter, prefer arguments:
// 1. quoted (capture 3; capture 4 or capture 5)
"('((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\")|" +
// 2. simple (capture 6)
"((?:\\\\.|[^\\\\()[\\]]|" + attributes + ")*)|" +
// 3. anything else (capture 2)
".*" +
")\\)|)",
// Leading and non-escaped trailing whitespace, capturing some non-whitespace characters preceding the latter
rwhitespace = new RegExp(whitespace + "+", "g"),
rtrim = new RegExp("^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g"),
rcomma = new RegExp("^" + whitespace + "*," + whitespace + "*"),
rcombinators = new RegExp("^" + whitespace + "*([>+~]|" + whitespace + ")" + whitespace + "*"),
rattributeQuotes = new RegExp("=" + whitespace + "*([^\\]'\"]*?)" + whitespace + "*\\]", "g"),
rpseudo = new RegExp(pseudos),
ridentifier = new RegExp("^" + identifier + "$"),
matchExpr = {
"ID": new RegExp("^#(" + characterEncoding + ")"),
"CLASS": new RegExp("^\\.(" + characterEncoding + ")"),
"TAG": new RegExp("^(" + characterEncoding.replace("w", "w*") + ")"),
"ATTR": new RegExp("^" + attributes),
"PSEUDO": new RegExp("^" + pseudos),
"CHILD": new RegExp("^:(only|first|last|nth|nth-last)-(child|of-type)(?:\\(" + whitespace +
"*(even|odd|(([+-]|)(\\d*)n|)" + whitespace + "*(?:([+-]|)" + whitespace +
"*(\\d+)|))" + whitespace + "*\\)|)", "i"),
"bool": new RegExp("^(?:" + booleans + ")$", "i"),
// For use in libraries implementing .is()
// We use this for POS matching in `select`
"needsContext": new RegExp("^" + whitespace + "*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\\(" +
whitespace + "*((?:-\\d)?\\d*)" + whitespace + "*\\)|)(?=[^-]|$)", "i")
},
rinputs = /^(?:input|select|textarea|button)$/i,
rheader = /^h\d$/i,
rnative = /^[^{]+\{\s*\[native \w/,
// Easily-parseable/retrievable ID or TAG or CLASS selectors
rquickExpr = /^(?:#([\w-]+)|(\w+)|\.([\w-]+))$/,
rsibling = /[+~]/,
rescape = /'|\\/g,
// CSS escapes http://www.w3.org/TR/CSS21/syndata.html#escaped-characters
runescape = new RegExp("\\\\([\\da-f]{1,6}" + whitespace + "?|(" + whitespace + ")|.)", "ig"),
funescape = function (_, escaped, escapedWhitespace) {
var high = "0x" + escaped - 0x10000;
// NaN means non-codepoint
// Support: Firefox<24
// Workaround erroneous numeric interpretation of +"0x"
return high !== high || escapedWhitespace ?
escaped :
high < 0 ?
// BMP codepoint
String.fromCharCode(high + 0x10000) :
// Supplemental Plane codepoint (surrogate pair)
String.fromCharCode(high >> 10 | 0xD800, high & 0x3FF | 0xDC00);
},
// Used for iframes
// See setDocument()
// Removing the function wrapper causes a "Permission Denied"
// error in IE
unloadHandler = function () {
setDocument();
};
// Optimize for push.apply( _, NodeList )
try {
push.apply(
(arr = slice.call(preferredDoc.childNodes)),
preferredDoc.childNodes
);
// Support: Android<4.0
// Detect silently failing push.apply
arr[preferredDoc.childNodes.length].nodeType;
} catch (e) {
push = {
apply: arr.length ?
// Leverage slice if possible
function (target, els) {
push_native.apply(target, slice.call(els));
} :
// Support: IE<9
// Otherwise append directly
function (target, els) {
var j = target.length,
i = 0;
// Can't trust NodeList.length
while ((target[j++] = els[i++])) { }
target.length = j - 1;
}
};
}
function Sizzle(selector, context, results, seed) {
var match, elem, m, nodeType,
// QSA vars
i, groups, old, nid, newContext, newSelector;
if ((context ? context.ownerDocument || context : preferredDoc) !== document) {
setDocument(context);
}
context = context || document;
results = results || [];
nodeType = context.nodeType;
if (typeof selector !== "string" || !selector ||
nodeType !== 1 && nodeType !== 9 && nodeType !== 11) {
return results;
}
if (!seed && documentIsHTML) {
// Try to shortcut find operations when possible (e.g., not under DocumentFragment)
if (nodeType !== 11 && (match = rquickExpr.exec(selector))) {
// Speed-up: Sizzle("#ID")
if ((m = match[1])) {
if (nodeType === 9) {
elem = context.getElementById(m);
// Check parentNode to catch when Blackberry 4.6 returns
// nodes that are no longer in the document (jQuery #6963)
if (elem && elem.parentNode) {
// Handle the case where IE, Opera, and Webkit return items
// by name instead of ID
if (elem.id === m) {
results.push(elem);
return results;
}
} else {
return results;
}
} else {
// Context is not a document
if (context.ownerDocument && (elem = context.ownerDocument.getElementById(m)) &&
contains(context, elem) && elem.id === m) {
results.push(elem);
return results;
}
}
// Speed-up: Sizzle("TAG")
} else if (match[2]) {
push.apply(results, context.getElementsByTagName(selector));
return results;
// Speed-up: Sizzle(".CLASS")
} else if ((m = match[3]) && support.getElementsByClassName) {
push.apply(results, context.getElementsByClassName(m));
return results;
}
}
// QSA path
if (support.qsa && (!rbuggyQSA || !rbuggyQSA.test(selector))) {
nid = old = expando;
newContext = context;
newSelector = nodeType !== 1 && selector;
// qSA works strangely on Element-rooted queries
// We can work around this by specifying an extra ID on the root
// and working up from there (Thanks to Andrew Dupont for the technique)
// IE 8 doesn't work on object elements
if (nodeType === 1 && context.nodeName.toLowerCase() !== "object") {
groups = tokenize(selector);
if ((old = context.getAttribute("id"))) {
nid = old.replace(rescape, "\\$&");
} else {
context.setAttribute("id", nid);
}
nid = "[id='" + nid + "'] ";
i = groups.length;
while (i--) {
groups[i] = nid + toSelector(groups[i]);
}
newContext = rsibling.test(selector) && testContext(context.parentNode) || context;
newSelector = groups.join(",");
}
if (newSelector) {
try {
push.apply(results,
newContext.querySelectorAll(newSelector)
);
return results;
} catch (qsaError) {
} finally {
if (!old) {
context.removeAttribute("id");
}
}
}
}
}
// All others
return select(selector.replace(rtrim, "$1"), context, results, seed);
}
/**
* Create key-value caches of limited size
* @returns {Function(string, Object)} Returns the Object data after storing it on itself with
* property name the (space-suffixed) string and (if the cache is larger than Expr.cacheLength)
* deleting the oldest entry
*/
function createCache() {
var keys = [];
function cache(key, value) {
// Use (key + " ") to avoid collision with native prototype properties (see Issue #157)
if (keys.push(key + " ") > Expr.cacheLength) {
// Only keep the most recent entries
delete cache[keys.shift()];
}
return (cache[key + " "] = value);
}
return cache;
}
/**
* Mark a function for special use by Sizzle
* @param {Function} fn The function to mark
*/
function markFunction(fn) {
fn[expando] = true;
return fn;
}
/**
* Support testing using an element
* @param {Function} fn Passed the created div and expects a boolean result
*/
function assert(fn) {
var div = document.createElement("div");
try {
return !!fn(div);
} catch (e) {
return false;
} finally {
// Remove from its parent by default
if (div.parentNode) {
div.parentNode.removeChild(div);
}
// release memory in IE
div = null;
}
}
/**
* Adds the same handler for all of the specified attrs
* @param {String} attrs Pipe-separated list of attributes
* @param {Function} handler The method that will be applied
*/
function addHandle(attrs, handler) {
var arr = attrs.split("|"),
i = attrs.length;
while (i--) {
Expr.attrHandle[arr[i]] = handler;
}
}
/**
* Checks document order of two siblings
* @param {Element} a
* @param {Element} b
* @returns {Number} Returns less than 0 if a precedes b, greater than 0 if a follows b
*/
function siblingCheck(a, b) {
var cur = b && a,
diff = cur && a.nodeType === 1 && b.nodeType === 1 &&
(~b.sourceIndex || MAX_NEGATIVE) -
(~a.sourceIndex || MAX_NEGATIVE);
// Use IE sourceIndex if available on both nodes
if (diff) {
return diff;
}
// Check if b follows a
if (cur) {
while ((cur = cur.nextSibling)) {
if (cur === b) {
return -1;
}
}
}
return a ? 1 : -1;
}
/**
* Returns a function to use in pseudos for input types
* @param {String} type
*/
function createInputPseudo(type) {
return function (elem) {
var name = elem.nodeName.toLowerCase();
return name === "input" && elem.type === type;
};
}
/**
* Returns a function to use in pseudos for buttons
* @param {String} type
*/
function createButtonPseudo(type) {
return function (elem) {
var name = elem.nodeName.toLowerCase();
return (name === "input" || name === "button") && elem.type === type;
};
}
/**
* Returns a function to use in pseudos for positionals
* @param {Function} fn
*/
function createPositionalPseudo(fn) {
return markFunction(function (argument) {
argument = +argument;
return markFunction(function (seed, matches) {
var j,
matchIndexes = fn([], seed.length, argument),
i = matchIndexes.length;
// Match elements found at the specified indexes
while (i--) {
if (seed[(j = matchIndexes[i])]) {
seed[j] = !(matches[j] = seed[j]);
}
}
});
});
}
/**
* Checks a node for validity as a Sizzle context
* @param {Element|Object=} context
* @returns {Element|Object|Boolean} The input node if acceptable, otherwise a falsy value
*/
function testContext(context) {
return context && typeof context.getElementsByTagName !== "undefined" && context;
}
// Expose support vars for convenience
support = Sizzle.support = {};
/**
* Detects XML nodes
* @param {Element|Object} elem An element or a document
* @returns {Boolean} True iff elem is a non-HTML XML node
*/
isXML = Sizzle.isXML = function (elem) {
// documentElement is verified for cases where it doesn't yet exist
// (such as loading iframes in IE - #4833)
var documentElement = elem && (elem.ownerDocument || elem).documentElement;
return documentElement ? documentElement.nodeName !== "HTML" : false;
};
/**
* Sets document-related variables once based on the current document
* @param {Element|Object} [doc] An element or document object to use to set the document
* @returns {Object} Returns the current document
*/
setDocument = Sizzle.setDocument = function (node) {
var hasCompare, parent,
doc = node ? node.ownerDocument || node : preferredDoc;
// If no document and documentElement is available, return
if (doc === document || doc.nodeType !== 9 || !doc.documentElement) {
return document;
}
// Set our document
document = doc;
docElem = doc.documentElement;
parent = doc.defaultView;
// Support: IE>8
// If iframe document is assigned to "document" variable and if iframe has been reloaded,
// IE will throw "permission denied" error when accessing "document" variable, see jQuery #13936
// IE6-8 do not support the defaultView property so parent will be undefined
if (parent && parent !== parent.top) {
// IE11 does not have attachEvent, so all must suffer
if (parent.addEventListener) {
parent.addEventListener("unload", unloadHandler, false);
} else if (parent.attachEvent) {
parent.attachEvent("onunload", unloadHandler);
}
}
/* Support tests
---------------------------------------------------------------------- */
documentIsHTML = !isXML(doc);
/* Attributes
---------------------------------------------------------------------- */
// Support: IE<8
// Verify that getAttribute really returns attributes and not properties
// (excepting IE8 booleans)
support.attributes = assert(function (div) {
div.className = "i";
return !div.getAttribute("className");
});
/* getElement(s)By*
---------------------------------------------------------------------- */
// Check if getElementsByTagName("*") returns only elements
support.getElementsByTagName = assert(function (div) {
div.appendChild(doc.createComment(""));
return !div.getElementsByTagName("*").length;
});
// Support: IE<9
support.getElementsByClassName = rnative.test(doc.getElementsByClassName);
// Support: IE<10
// Check if getElementById returns elements by name
// The broken getElementById methods don't pick up programatically-set names,
// so use a roundabout getElementsByName test
support.getById = assert(function (div) {
docElem.appendChild(div).id = expando;
return !doc.getElementsByName || !doc.getElementsByName(expando).length;
});
// ID find and filter
if (support.getById) {
Expr.find["ID"] = function (id, context) {
if (typeof context.getElementById !== "undefined" && documentIsHTML) {
var m = context.getElementById(id);
// Check parentNode to catch when Blackberry 4.6 returns
// nodes that are no longer in the document #6963
return m && m.parentNode ? [m] : [];
}
};
Expr.filter["ID"] = function (id) {
var attrId = id.replace(runescape, funescape);
return function (elem) {
return elem.getAttribute("id") === attrId;
};
};
} else {
// Support: IE6/7
// getElementById is not reliable as a find shortcut
delete Expr.find["ID"];
Expr.filter["ID"] = function (id) {
var attrId = id.replace(runescape, funescape);
return function (elem) {
var node = typeof elem.getAttributeNode !== "undefined" && elem.getAttributeNode("id");
return node && node.value === attrId;
};
};
}
// Tag
Expr.find["TAG"] = support.getElementsByTagName ?
function (tag, context) {
if (typeof context.getElementsByTagName !== "undefined") {
return context.getElementsByTagName(tag);
// DocumentFragment nodes don't have gEBTN
} else if (support.qsa) {
return context.querySelectorAll(tag);
}
} :
function (tag, context) {
var elem,
tmp = [],
i = 0,
// By happy coincidence, a (broken) gEBTN appears on DocumentFragment nodes too
results = context.getElementsByTagName(tag);
// Filter out possible comments
if (tag === "*") {
while ((elem = results[i++])) {
if (elem.nodeType === 1) {
tmp.push(elem);
}
}
return tmp;
}
return results;
};
// Class
Expr.find["CLASS"] = support.getElementsByClassName && function (className, context) {
if (documentIsHTML) {
return context.getElementsByClassName(className);
}
};
/* QSA/matchesSelector
---------------------------------------------------------------------- */
// QSA and matchesSelector support
// matchesSelector(:active) reports false when true (IE9/Opera 11.5)
rbuggyMatches = [];
// qSa(:focus) reports false when true (Chrome 21)
// We allow this because of a bug in IE8/9 that throws an error
// whenever `document.activeElement` is accessed on an iframe
// So, we allow :focus to pass through QSA all the time to avoid the IE error
// See http://bugs.jquery.com/ticket/13378
rbuggyQSA = [];
if ((support.qsa = rnative.test(doc.querySelectorAll))) {
// Build QSA regex
// Regex strategy adopted from Diego Perini
assert(function (div) {
// Select is set to empty string on purpose
// This is to test IE's treatment of not explicitly
// setting a boolean content attribute,
// since its presence should be enough
// http://bugs.jquery.com/ticket/12359
docElem.appendChild(div).innerHTML = "<a id='" + expando + "'></a>" +
"<select id='" + expando + "-\f]' msallowcapture=''>" +
"<option selected=''></option></select>";
// Support: IE8, Opera 11-12.16
// Nothing should be selected when empty strings follow ^= or $= or *=
// The test attribute must be unknown in Opera but "safe" for WinRT
// http://msdn.microsoft.com/en-us/library/ie/hh465388.aspx#attribute_section
if (div.querySelectorAll("[msallowcapture^='']").length) {
rbuggyQSA.push("[*^$]=" + whitespace + "*(?:''|\"\")");
}
// Support: IE8
// Boolean attributes and "value" are not treated correctly
if (!div.querySelectorAll("[selected]").length) {
rbuggyQSA.push("\\[" + whitespace + "*(?:value|" + booleans + ")");
}
// Support: Chrome<29, Android<4.2+, Safari<7.0+, iOS<7.0+, PhantomJS<1.9.7+
if (!div.querySelectorAll("[id~=" + expando + "-]").length) {
rbuggyQSA.push("~=");
}
// Webkit/Opera - :checked should return selected option elements
// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
// IE8 throws error here and will not see later tests
if (!div.querySelectorAll(":checked").length) {
rbuggyQSA.push(":checked");
}
// Support: Safari 8+, iOS 8+
// https://bugs.webkit.org/show_bug.cgi?id=136851
// In-page `selector#id sibing-combinator selector` fails
if (!div.querySelectorAll("a#" + expando + "+*").length) {
rbuggyQSA.push(".#.+[+~]");
}
});
assert(function (div) {
// Support: Windows 8 Native Apps
// The type and name attributes are restricted during .innerHTML assignment
var input = doc.createElement("input");
input.setAttribute("type", "hidden");
div.appendChild(input).setAttribute("name", "D");
// Support: IE8
// Enforce case-sensitivity of name attribute
if (div.querySelectorAll("[name=d]").length) {
rbuggyQSA.push("name" + whitespace + "*[*^$|!~]?=");
}
// FF 3.5 - :enabled/:disabled and hidden elements (hidden elements are still enabled)
// IE8 throws error here and will not see later tests
if (!div.querySelectorAll(":enabled").length) {
rbuggyQSA.push(":enabled", ":disabled");
}
// Opera 10-11 does not throw on post-comma invalid pseudos
div.querySelectorAll("*,:x");
rbuggyQSA.push(",.*:");
});
}
if ((support.matchesSelector = rnative.test((matches = docElem.matches ||
docElem.webkitMatchesSelector ||
docElem.mozMatchesSelector ||
docElem.oMatchesSelector ||
docElem.msMatchesSelector)))) {
assert(function (div) {
// Check to see if it's possible to do matchesSelector
// on a disconnected node (IE 9)
support.disconnectedMatch = matches.call(div, "div");
// This should fail with an exception
// Gecko does not error, returns false instead
matches.call(div, "[s!='']:x");
rbuggyMatches.push("!=", pseudos);
});
}
rbuggyQSA = rbuggyQSA.length && new RegExp(rbuggyQSA.join("|"));
rbuggyMatches = rbuggyMatches.length && new RegExp(rbuggyMatches.join("|"));
/* Contains
---------------------------------------------------------------------- */
hasCompare = rnative.test(docElem.compareDocumentPosition);
// Element contains another
// Purposefully does not implement inclusive descendent
// As in, an element does not contain itself
contains = hasCompare || rnative.test(docElem.contains) ?
function (a, b) {
var adown = a.nodeType === 9 ? a.documentElement : a,
bup = b && b.parentNode;
return a === bup || !!(bup && bup.nodeType === 1 && (
adown.contains ?
adown.contains(bup) :
a.compareDocumentPosition && a.compareDocumentPosition(bup) & 16
));
} :
function (a, b) {
if (b) {
while ((b = b.parentNode)) {
if (b === a) {
return true;
}
}
}
return false;
};
/* Sorting
---------------------------------------------------------------------- */
// Document order sorting
sortOrder = hasCompare ?
function (a, b) {
// Flag for duplicate removal
if (a === b) {
hasDuplicate = true;
return 0;
}
// Sort on method existence if only one input has compareDocumentPosition
var compare = !a.compareDocumentPosition - !b.compareDocumentPosition;
if (compare) {
return compare;
}
// Calculate position if both inputs belong to the same document
compare = (a.ownerDocument || a) === (b.ownerDocument || b) ?
a.compareDocumentPosition(b) :
// Otherwise we know they are disconnected
1;
// Disconnected nodes
if (compare & 1 ||
(!support.sortDetached && b.compareDocumentPosition(a) === compare)) {
// Choose the first element that is related to our preferred document
if (a === doc || a.ownerDocument === preferredDoc && contains(preferredDoc, a)) {
return -1;
}
if (b === doc || b.ownerDocument === preferredDoc && contains(preferredDoc, b)) {
return 1;
}
// Maintain original order
return sortInput ?
(indexOf(sortInput, a) - indexOf(sortInput, b)) :
0;
}
return compare & 4 ? -1 : 1;
} :
function (a, b) {
// Exit early if the nodes are identical
if (a === b) {
hasDuplicate = true;
return 0;
}
var cur,
i = 0,
aup = a.parentNode,
bup = b.parentNode,
ap = [a],
bp = [b];
// Parentless nodes are either documents or disconnected
if (!aup || !bup) {
return a === doc ? -1 :
b === doc ? 1 :
aup ? -1 :
bup ? 1 :
sortInput ?
(indexOf(sortInput, a) - indexOf(sortInput, b)) :
0;
// If the nodes are siblings, we can do a quick check
} else if (aup === bup) {
return siblingCheck(a, b);
}
// Otherwise we need full lists of their ancestors for comparison
cur = a;
while ((cur = cur.parentNode)) {
ap.unshift(cur);
}
cur = b;
while ((cur = cur.parentNode)) {
bp.unshift(cur);
}
// Walk down the tree looking for a discrepancy
while (ap[i] === bp[i]) {
i++;
}
return i ?
// Do a sibling check if the nodes have a common ancestor
siblingCheck(ap[i], bp[i]) :
// Otherwise nodes in our document sort first
ap[i] === preferredDoc ? -1 :
bp[i] === preferredDoc ? 1 :
0;
};
return doc;
};
Sizzle.matches = function (expr, elements) {
return Sizzle(expr, null, null, elements);
};
Sizzle.matchesSelector = function (elem, expr) {
// Set document vars if needed
if ((elem.ownerDocument || elem) !== document) {
setDocument(elem);
}
// Make sure that attribute selectors are quoted
expr = expr.replace(rattributeQuotes, "='$1']");
if (support.matchesSelector && documentIsHTML &&
(!rbuggyMatches || !rbuggyMatches.test(expr)) &&
(!rbuggyQSA || !rbuggyQSA.test(expr))) {
try {
var ret = matches.call(elem, expr);
// IE 9's matchesSelector returns false on disconnected nodes
if (ret || support.disconnectedMatch ||
// As well, disconnected nodes are said to be in a document
// fragment in IE 9
elem.document && elem.document.nodeType !== 11) {
return ret;
}
} catch (e) { }
}
return Sizzle(expr, document, null, [elem]).length > 0;
};
Sizzle.contains = function (context, elem) {
// Set document vars if needed
if ((context.ownerDocument || context) !== document) {
setDocument(context);
}
return contains(context, elem);
};
Sizzle.attr = function (elem, name) {
// Set document vars if needed
if ((elem.ownerDocument || elem) !== document) {
setDocument(elem);
}
var fn = Expr.attrHandle[name.toLowerCase()],
// Don't get fooled by Object.prototype properties (jQuery #13807)
val = fn && hasOwn.call(Expr.attrHandle, name.toLowerCase()) ?
fn(elem, name, !documentIsHTML) :
undefined;
return val !== undefined ?
val :
support.attributes || !documentIsHTML ?
elem.getAttribute(name) :
(val = elem.getAttributeNode(name)) && val.specified ?
val.value :
null;
};
Sizzle.error = function (msg) {
throw new Error("Syntax error, unrecognized expression: " + msg);
};
/**
* Document sorting and removing duplicates
* @param {ArrayLike} results
*/
Sizzle.uniqueSort = function (results) {
var elem,
duplicates = [],
j = 0,
i = 0;
// Unless we *know* we can detect duplicates, assume their presence
hasDuplicate = !support.detectDuplicates;
sortInput = !support.sortStable && results.slice(0);
results.sort(sortOrder);
if (hasDuplicate) {
while ((elem = results[i++])) {
if (elem === results[i]) {
j = duplicates.push(i);
}
}
while (j--) {
results.splice(duplicates[j], 1);
}
}
// Clear input after sorting to release objects
// See https://github.com/jquery/sizzle/pull/225
sortInput = null;
return results;
};
/**
* Utility function for retrieving the text value of an array of DOM nodes
* @param {Array|Element} elem
*/
getText = Sizzle.getText = function (elem) {
var node,
ret = "",
i = 0,
nodeType = elem.nodeType;
if (!nodeType) {
// If no nodeType, this is expected to be an array
while ((node = elem[i++])) {
// Do not traverse comment nodes
ret += getText(node);
}
} else if (nodeType === 1 || nodeType === 9 || nodeType === 11) {
// Use textContent for elements
// innerText usage removed for consistency of new lines (jQuery #11153)
if (typeof elem.textContent === "string") {
return elem.textContent;
} else {
// Traverse its children
for (elem = elem.firstChild; elem; elem = elem.nextSibling) {
ret += getText(elem);
}
}
} else if (nodeType === 3 || nodeType === 4) {
return elem.nodeValue;
}
// Do not include comment or processing instruction nodes
return ret;
};
Expr = Sizzle.selectors = {
// Can be adjusted by the user
cacheLength: 50,
createPseudo: markFunction,
match: matchExpr,
attrHandle: {},
find: {},
relative: {
">": { dir: "parentNode", first: true },
" ": { dir: "parentNode" },
"+": { dir: "previousSibling", first: true },
"~": { dir: "previousSibling" }
},
preFilter: {
"ATTR": function (match) {
match[1] = match[1].replace(runescape, funescape);
// Move the given value to match[3] whether quoted or unquoted
match[3] = (match[3] || match[4] || match[5] || "").replace(runescape, funescape);
if (match[2] === "~=") {
match[3] = " " + match[3] + " ";
}
return match.slice(0, 4);
},
"CHILD": function (match) {
/* matches from matchExpr["CHILD"]
1 type (only|nth|...)
2 what (child|of-type)
3 argument (even|odd|\d*|\d*n([+-]\d+)?|...)
4 xn-component of xn+y argument ([+-]?\d*n|)
5 sign of xn-component
6 x of xn-component
7 sign of y-component
8 y of y-component
*/
match[1] = match[1].toLowerCase();
if (match[1].slice(0, 3) === "nth") {
// nth-* requires argument
if (!match[3]) {
Sizzle.error(match[0]);
}
// numeric x and y parameters for Expr.filter.CHILD
// remember that false/true cast respectively to 0/1
match[4] = +(match[4] ? match[5] + (match[6] || 1) : 2 * (match[3] === "even" || match[3] === "odd"));
match[5] = +((match[7] + match[8]) || match[3] === "odd");
// other types prohibit arguments
} else if (match[3]) {
Sizzle.error(match[0]);
}
return match;
},
"PSEUDO": function (match) {
var excess,
unquoted = !match[6] && match[2];
if (matchExpr["CHILD"].test(match[0])) {
return null;
}
// Accept quoted arguments as-is
if (match[3]) {
match[2] = match[4] || match[5] || "";
// Strip excess characters from unquoted arguments
} else if (unquoted && rpseudo.test(unquoted) &&
// Get excess from tokenize (recursively)
(excess = tokenize(unquoted, true)) &&
// advance to the next closing parenthesis
(excess = unquoted.indexOf(")", unquoted.length - excess) - unquoted.length)) {
// excess is a negative index
match[0] = match[0].slice(0, excess);
match[2] = unquoted.slice(0, excess);
}
// Return only captures needed by the pseudo filter method (type and argument)
return match.slice(0, 3);
}
},
filter: {
"TAG": function (nodeNameSelector) {
var nodeName = nodeNameSelector.replace(runescape, funescape).toLowerCase();
return nodeNameSelector === "*" ?
function () { return true; } :
function (elem) {
return elem.nodeName && elem.nodeName.toLowerCase() === nodeName;
};
},
"CLASS": function (className) {
var pattern = classCache[className + " "];
return pattern ||
(pattern = new RegExp("(^|" + whitespace + ")" + className + "(" + whitespace + "|$)")) &&
classCache(className, function (elem) {
return pattern.test(typeof elem.className === "string" && elem.className || typeof elem.getAttribute !== "undefined" && elem.getAttribute("class") || "");
});
},
"ATTR": function (name, operator, check) {
return function (elem) {
var result = Sizzle.attr(elem, name);
if (result == null) {
return operator === "!=";
}
if (!operator) {
return true;
}
result += "";
return operator === "=" ? result === check :
operator === "!=" ? result !== check :
operator === "^=" ? check && result.indexOf(check) === 0 :
operator === "*=" ? check && result.indexOf(check) > -1 :
operator === "$=" ? check && result.slice(-check.length) === check :
operator === "~=" ? (" " + result.replace(rwhitespace, " ") + " ").indexOf(check) > -1 :
operator === "|=" ? result === check || result.slice(0, check.length + 1) === check + "-" :
false;
};
},
"CHILD": function (type, what, argument, first, last) {
var simple = type.slice(0, 3) !== "nth",
forward = type.slice(-4) !== "last",
ofType = what === "of-type";
return first === 1 && last === 0 ?
// Shortcut for :nth-*(n)
function (elem) {
return !!elem.parentNode;
} :
function (elem, context, xml) {
var cache, outerCache, node, diff, nodeIndex, start,
dir = simple !== forward ? "nextSibling" : "previousSibling",
parent = elem.parentNode,
name = ofType && elem.nodeName.toLowerCase(),
useCache = !xml && !ofType;
if (parent) {
// :(first|last|only)-(child|of-type)
if (simple) {
while (dir) {
node = elem;
while ((node = node[dir])) {
if (ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1) {
return false;
}
}
// Reverse direction for :only-* (if we haven't yet done so)
start = dir = type === "only" && !start && "nextSibling";
}
return true;
}
start = [forward ? parent.firstChild : parent.lastChild];
// non-xml :nth-child(...) stores cache data on `parent`
if (forward && useCache) {
// Seek `elem` from a previously-cached index
outerCache = parent[expando] || (parent[expando] = {});
cache = outerCache[type] || [];
nodeIndex = cache[0] === dirruns && cache[1];
diff = cache[0] === dirruns && cache[2];
node = nodeIndex && parent.childNodes[nodeIndex];
while ((node = ++nodeIndex && node && node[dir] ||
// Fallback to seeking `elem` from the start
(diff = nodeIndex = 0) || start.pop())) {
// When found, cache indexes on `parent` and break
if (node.nodeType === 1 && ++diff && node === elem) {
outerCache[type] = [dirruns, nodeIndex, diff];
break;
}
}
// Use previously-cached element index if available
} else if (useCache && (cache = (elem[expando] || (elem[expando] = {}))[type]) && cache[0] === dirruns) {
diff = cache[1];
// xml :nth-child(...) or :nth-last-child(...) or :nth(-last)?-of-type(...)
} else {
// Use the same loop as above to seek `elem` from the start
while ((node = ++nodeIndex && node && node[dir] ||
(diff = nodeIndex = 0) || start.pop())) {
if ((ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1) && ++diff) {
// Cache the index of each encountered element
if (useCache) {
(node[expando] || (node[expando] = {}))[type] = [dirruns, diff];
}
if (node === elem) {
break;
}
}
}
}
// Incorporate the offset, then check against cycle size
diff -= last;
return diff === first || (diff % first === 0 && diff / first >= 0);
}
};
},
"PSEUDO": function (pseudo, argument) {
// pseudo-class names are case-insensitive
// http://www.w3.org/TR/selectors/#pseudo-classes
// Prioritize by case sensitivity in case custom pseudos are added with uppercase letters
// Remember that setFilters inherits from pseudos
var args,
fn = Expr.pseudos[pseudo] || Expr.setFilters[pseudo.toLowerCase()] ||
Sizzle.error("unsupported pseudo: " + pseudo);
// The user may use createPseudo to indicate that
// arguments are needed to create the filter function
// just as Sizzle does
if (fn[expando]) {
return fn(argument);
}
// But maintain support for old signatures
if (fn.length > 1) {
args = [pseudo, pseudo, "", argument];
return Expr.setFilters.hasOwnProperty(pseudo.toLowerCase()) ?
markFunction(function (seed, matches) {
var idx,
matched = fn(seed, argument),
i = matched.length;
while (i--) {
idx = indexOf(seed, matched[i]);
seed[idx] = !(matches[idx] = matched[i]);
}
}) :
function (elem) {
return fn(elem, 0, args);
};
}
return fn;
}
},
pseudos: {
// Potentially complex pseudos
"not": markFunction(function (selector) {
// Trim the selector passed to compile
// to avoid treating leading and trailing
// spaces as combinators
var input = [],
results = [],
matcher = compile(selector.replace(rtrim, "$1"));
return matcher[expando] ?
markFunction(function (seed, matches, context, xml) {
var elem,
unmatched = matcher(seed, null, xml, []),
i = seed.length;
// Match elements unmatched by `matcher`
while (i--) {
if ((elem = unmatched[i])) {
seed[i] = !(matches[i] = elem);
}
}
}) :
function (elem, context, xml) {
input[0] = elem;
matcher(input, null, xml, results);
// Don't keep the element (issue #299)
input[0] = null;
return !results.pop();
};
}),
"has": markFunction(function (selector) {
return function (elem) {
return Sizzle(selector, elem).length > 0;
};
}),
"contains": markFunction(function (text) {
text = text.replace(runescape, funescape);
return function (elem) {
return (elem.textContent || elem.innerText || getText(elem)).indexOf(text) > -1;
};
}),
// "Whether an element is represented by a :lang() selector
// is based solely on the element's language value
// being equal to the identifier C,
// or beginning with the identifier C immediately followed by "-".
// The matching of C against the element's language value is performed case-insensitively.
// The identifier C does not have to be a valid language name."
// http://www.w3.org/TR/selectors/#lang-pseudo
"lang": markFunction(function (lang) {
// lang value must be a valid identifier
if (!ridentifier.test(lang || "")) {
Sizzle.error("unsupported lang: " + lang);
}
lang = lang.replace(runescape, funescape).toLowerCase();
return function (elem) {
var elemLang;
do {
if ((elemLang = documentIsHTML ?
elem.lang :
elem.getAttribute("xml:lang") || elem.getAttribute("lang"))) {
elemLang = elemLang.toLowerCase();
return elemLang === lang || elemLang.indexOf(lang + "-") === 0;
}
} while ((elem = elem.parentNode) && elem.nodeType === 1);
return false;
};
}),
// Miscellaneous
"target": function (elem) {
var hash = window.location && window.location.hash;
return hash && hash.slice(1) === elem.id;
},
"root": function (elem) {
return elem === docElem;
},
"focus": function (elem) {
return elem === document.activeElement && (!document.hasFocus || document.hasFocus()) && !!(elem.type || elem.href || ~elem.tabIndex);
},
// Boolean properties
"enabled": function (elem) {
return elem.disabled === false;
},
"disabled": function (elem) {
return elem.disabled === true;
},
"checked": function (elem) {
// In CSS3, :checked should return both checked and selected elements
// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
var nodeName = elem.nodeName.toLowerCase();
return (nodeName === "input" && !!elem.checked) || (nodeName === "option" && !!elem.selected);
},
"selected": function (elem) {
// Accessing this property makes selected-by-default
// options in Safari work properly
if (elem.parentNode) {
elem.parentNode.selectedIndex;
}
return elem.selected === true;
},
// Contents
"empty": function (elem) {
// http://www.w3.org/TR/selectors/#empty-pseudo
// :empty is negated by element (1) or content nodes (text: 3; cdata: 4; entity ref: 5),
// but not by others (comment: 8; processing instruction: 7; etc.)
// nodeType < 6 works because attributes (2) do not appear as children
for (elem = elem.firstChild; elem; elem = elem.nextSibling) {
if (elem.nodeType < 6) {
return false;
}
}
return true;
},
"parent": function (elem) {
return !Expr.pseudos["empty"](elem);
},
// Element/input types
"header": function (elem) {
return rheader.test(elem.nodeName);
},
"input": function (elem) {
return rinputs.test(elem.nodeName);
},
"button": function (elem) {
var name = elem.nodeName.toLowerCase();
return name === "input" && elem.type === "button" || name === "button";
},
"text": function (elem) {
var attr;
return elem.nodeName.toLowerCase() === "input" &&
elem.type === "text" &&
// Support: IE<8
// New HTML5 attribute values (e.g., "search") appear with elem.type === "text"
((attr = elem.getAttribute("type")) == null || attr.toLowerCase() === "text");
},
// Position-in-collection
"first": createPositionalPseudo(function () {
return [0];
}),
"last": createPositionalPseudo(function (matchIndexes, length) {
return [length - 1];
}),
"eq": createPositionalPseudo(function (matchIndexes, length, argument) {
return [argument < 0 ? argument + length : argument];
}),
"even": createPositionalPseudo(function (matchIndexes, length) {
var i = 0;
for (; i < length; i += 2) {
matchIndexes.push(i);
}
return matchIndexes;
}),
"odd": createPositionalPseudo(function (matchIndexes, length) {
var i = 1;
for (; i < length; i += 2) {
matchIndexes.push(i);
}
return matchIndexes;
}),
"lt": createPositionalPseudo(function (matchIndexes, length, argument) {
var i = argument < 0 ? argument + length : argument;
for (; --i >= 0;) {
matchIndexes.push(i);
}
return matchIndexes;
}),
"gt": createPositionalPseudo(function (matchIndexes, length, argument) {
var i = argument < 0 ? argument + length : argument;
for (; ++i < length;) {
matchIndexes.push(i);
}
return matchIndexes;
})
}
};
Expr.pseudos["nth"] = Expr.pseudos["eq"];
// Add button/input type pseudos
for (i in { radio: true, checkbox: true, file: true, password: true, image: true }) {
Expr.pseudos[i] = createInputPseudo(i);
}
for (i in { submit: true, reset: true }) {
Expr.pseudos[i] = createButtonPseudo(i);
}
// Easy API for creating new setFilters
function setFilters() { }
setFilters.prototype = Expr.filters = Expr.pseudos;
Expr.setFilters = new setFilters();
tokenize = Sizzle.tokenize = function (selector, parseOnly) {
var matched, match, tokens, type,
soFar, groups, preFilters,
cached = tokenCache[selector + " "];
if (cached) {
return parseOnly ? 0 : cached.slice(0);
}
soFar = selector;
groups = [];
preFilters = Expr.preFilter;
while (soFar) {
// Comma and first run
if (!matched || (match = rcomma.exec(soFar))) {
if (match) {
// Don't consume trailing commas as valid
soFar = soFar.slice(match[0].length) || soFar;
}
groups.push((tokens = []));
}
matched = false;
// Combinators
if ((match = rcombinators.exec(soFar))) {
matched = match.shift();
tokens.push({
value: matched,
// Cast descendant combinators to space
type: match[0].replace(rtrim, " ")
});
soFar = soFar.slice(matched.length);
}
// Filters
for (type in Expr.filter) {
if ((match = matchExpr[type].exec(soFar)) && (!preFilters[type] ||
(match = preFilters[type](match)))) {
matched = match.shift();
tokens.push({
value: matched,
type: type,
matches: match
});
soFar = soFar.slice(matched.length);
}
}
if (!matched) {
break;
}
}
// Return the length of the invalid excess
// if we're just parsing
// Otherwise, throw an error or return tokens
return parseOnly ?
soFar.length :
soFar ?
Sizzle.error(selector) :
// Cache the tokens
tokenCache(selector, groups).slice(0);
};
function toSelector(tokens) {
var i = 0,
len = tokens.length,
selector = "";
for (; i < len; i++) {
selector += tokens[i].value;
}
return selector;
}
function addCombinator(matcher, combinator, base) {
var dir = combinator.dir,
checkNonElements = base && dir === "parentNode",
doneName = done++;
return combinator.first ?
// Check against closest ancestor/preceding element
function (elem, context, xml) {
while ((elem = elem[dir])) {
if (elem.nodeType === 1 || checkNonElements) {
return matcher(elem, context, xml);
}
}
} :
// Check against all ancestor/preceding elements
function (elem, context, xml) {
var oldCache, outerCache,
newCache = [dirruns, doneName];
// We can't set arbitrary data on XML nodes, so they don't benefit from dir caching
if (xml) {
while ((elem = elem[dir])) {
if (elem.nodeType === 1 || checkNonElements) {
if (matcher(elem, context, xml)) {
return true;
}
}
}
} else {
while ((elem = elem[dir])) {
if (elem.nodeType === 1 || checkNonElements) {
outerCache = elem[expando] || (elem[expando] = {});
if ((oldCache = outerCache[dir]) &&
oldCache[0] === dirruns && oldCache[1] === doneName) {
// Assign to newCache so results back-propagate to previous elements
return (newCache[2] = oldCache[2]);
} else {
// Reuse newcache so results back-propagate to previous elements
outerCache[dir] = newCache;
// A match means we're done; a fail means we have to keep checking
if ((newCache[2] = matcher(elem, context, xml))) {
return true;
}
}
}
}
}
};
}
function elementMatcher(matchers) {
return matchers.length > 1 ?
function (elem, context, xml) {
var i = matchers.length;
while (i--) {
if (!matchers[i](elem, context, xml)) {
return false;
}
}
return true;
} :
matchers[0];
}
function multipleContexts(selector, contexts, results) {
var i = 0,
len = contexts.length;
for (; i < len; i++) {
Sizzle(selector, contexts[i], results);
}
return results;
}
function condense(unmatched, map, filter, context, xml) {
var elem,
newUnmatched = [],
i = 0,
len = unmatched.length,
mapped = map != null;
for (; i < len; i++) {
if ((elem = unmatched[i])) {
if (!filter || filter(elem, context, xml)) {
newUnmatched.push(elem);
if (mapped) {
map.push(i);
}
}
}
}
return newUnmatched;
}
function setMatcher(preFilter, selector, matcher, postFilter, postFinder, postSelector) {
if (postFilter && !postFilter[expando]) {
postFilter = setMatcher(postFilter);
}
if (postFinder && !postFinder[expando]) {
postFinder = setMatcher(postFinder, postSelector);
}
return markFunction(function (seed, results, context, xml) {
var temp, i, elem,
preMap = [],
postMap = [],
preexisting = results.length,
// Get initial elements from seed or context
elems = seed || multipleContexts(selector || "*", context.nodeType ? [context] : context, []),
// Prefilter to get matcher input, preserving a map for seed-results synchronization
matcherIn = preFilter && (seed || !selector) ?
condense(elems, preMap, preFilter, context, xml) :
elems,
matcherOut = matcher ?
// If we have a postFinder, or filtered seed, or non-seed postFilter or preexisting results,
postFinder || (seed ? preFilter : preexisting || postFilter) ?
// ...intermediate processing is necessary
[] :
// ...otherwise use results directly
results :
matcherIn;
// Find primary matches
if (matcher) {
matcher(matcherIn, matcherOut, context, xml);
}
// Apply postFilter
if (postFilter) {
temp = condense(matcherOut, postMap);
postFilter(temp, [], context, xml);
// Un-match failing elements by moving them back to matcherIn
i = temp.length;
while (i--) {
if ((elem = temp[i])) {
matcherOut[postMap[i]] = !(matcherIn[postMap[i]] = elem);
}
}
}
if (seed) {
if (postFinder || preFilter) {
if (postFinder) {
// Get the final matcherOut by condensing this intermediate into postFinder contexts
temp = [];
i = matcherOut.length;
while (i--) {
if ((elem = matcherOut[i])) {
// Restore matcherIn since elem is not yet a final match
temp.push((matcherIn[i] = elem));
}
}
postFinder(null, (matcherOut = []), temp, xml);
}
// Move matched elements from seed to results to keep them synchronized
i = matcherOut.length;
while (i--) {
if ((elem = matcherOut[i]) &&
(temp = postFinder ? indexOf(seed, elem) : preMap[i]) > -1) {
seed[temp] = !(results[temp] = elem);
}
}
}
// Add elements to results, through postFinder if defined
} else {
matcherOut = condense(
matcherOut === results ?
matcherOut.splice(preexisting, matcherOut.length) :
matcherOut
);
if (postFinder) {
postFinder(null, results, matcherOut, xml);
} else {
push.apply(results, matcherOut);
}
}
});
}
function matcherFromTokens(tokens) {
var checkContext, matcher, j,
len = tokens.length,
leadingRelative = Expr.relative[tokens[0].type],
implicitRelative = leadingRelative || Expr.relative[" "],
i = leadingRelative ? 1 : 0,
// The foundational matcher ensures that elements are reachable from top-level context(s)
matchContext = addCombinator(function (elem) {
return elem === checkContext;
}, implicitRelative, true),
matchAnyContext = addCombinator(function (elem) {
return indexOf(checkContext, elem) > -1;
}, implicitRelative, true),
matchers = [function (elem, context, xml) {
var ret = (!leadingRelative && (xml || context !== outermostContext)) || (
(checkContext = context).nodeType ?
matchContext(elem, context, xml) :
matchAnyContext(elem, context, xml));
// Avoid hanging onto element (issue #299)
checkContext = null;
return ret;
}];
for (; i < len; i++) {
if ((matcher = Expr.relative[tokens[i].type])) {
matchers = [addCombinator(elementMatcher(matchers), matcher)];
} else {
matcher = Expr.filter[tokens[i].type].apply(null, tokens[i].matches);
// Return special upon seeing a positional matcher
if (matcher[expando]) {
// Find the next relative operator (if any) for proper handling
j = ++i;
for (; j < len; j++) {
if (Expr.relative[tokens[j].type]) {
break;
}
}
return setMatcher(
i > 1 && elementMatcher(matchers),
i > 1 && toSelector(
// If the preceding token was a descendant combinator, insert an implicit any-element `*`
tokens.slice(0, i - 1).concat({ value: tokens[i - 2].type === " " ? "*" : "" })
).replace(rtrim, "$1"),
matcher,
i < j && matcherFromTokens(tokens.slice(i, j)),
j < len && matcherFromTokens((tokens = tokens.slice(j))),
j < len && toSelector(tokens)
);
}
matchers.push(matcher);
}
}
return elementMatcher(matchers);
}
function matcherFromGroupMatchers(elementMatchers, setMatchers) {
var bySet = setMatchers.length > 0,
byElement = elementMatchers.length > 0,
superMatcher = function (seed, context, xml, results, outermost) {
var elem, j, matcher,
matchedCount = 0,
i = "0",
unmatched = seed && [],
setMatched = [],
contextBackup = outermostContext,
// We must always have either seed elements or outermost context
elems = seed || byElement && Expr.find["TAG"]("*", outermost),
// Use integer dirruns iff this is the outermost matcher
dirrunsUnique = (dirruns += contextBackup == null ? 1 : Math.random() || 0.1),
len = elems.length;
if (outermost) {
outermostContext = context !== document && context;
}
// Add elements passing elementMatchers directly to results
// Keep `i` a string if there are no elements so `matchedCount` will be "00" below
// Support: IE<9, Safari
// Tolerate NodeList properties (IE: "length"; Safari: <number>) matching elements by id
for (; i !== len && (elem = elems[i]) != null; i++) {
if (byElement && elem) {
j = 0;
while ((matcher = elementMatchers[j++])) {
if (matcher(elem, context, xml)) {
results.push(elem);
break;
}
}
if (outermost) {
dirruns = dirrunsUnique;
}
}
// Track unmatched elements for set filters
if (bySet) {
// They will have gone through all possible matchers
if ((elem = !matcher && elem)) {
matchedCount--;
}
// Lengthen the array for every element, matched or not
if (seed) {
unmatched.push(elem);
}
}
}
// Apply set filters to unmatched elements
matchedCount += i;
if (bySet && i !== matchedCount) {
j = 0;
while ((matcher = setMatchers[j++])) {
matcher(unmatched, setMatched, context, xml);
}
if (seed) {
// Reintegrate element matches to eliminate the need for sorting
if (matchedCount > 0) {
while (i--) {
if (!(unmatched[i] || setMatched[i])) {
setMatched[i] = pop.call(results);
}
}
}
// Discard index placeholder values to get only actual matches
setMatched = condense(setMatched);
}
// Add matches to results
push.apply(results, setMatched);
// Seedless set matches succeeding multiple successful matchers stipulate sorting
if (outermost && !seed && setMatched.length > 0 &&
(matchedCount + setMatchers.length) > 1) {
Sizzle.uniqueSort(results);
}
}
// Override manipulation of globals by nested matchers
if (outermost) {
dirruns = dirrunsUnique;
outermostContext = contextBackup;
}
return unmatched;
};
return bySet ?
markFunction(superMatcher) :
superMatcher;
}
compile = Sizzle.compile = function (selector, match /* Internal Use Only */) {
var i,
setMatchers = [],
elementMatchers = [],
cached = compilerCache[selector + " "];
if (!cached) {
// Generate a function of recursive functions that can be used to check each element
if (!match) {
match = tokenize(selector);
}
i = match.length;
while (i--) {
cached = matcherFromTokens(match[i]);
if (cached[expando]) {
setMatchers.push(cached);
} else {
elementMatchers.push(cached);
}
}
// Cache the compiled function
cached = compilerCache(selector, matcherFromGroupMatchers(elementMatchers, setMatchers));
// Save selector and tokenization
cached.selector = selector;
}
return cached;
};
/**
* A low-level selection function that works with Sizzle's compiled
* selector functions
* @param {String|Function} selector A selector or a pre-compiled
* selector function built with Sizzle.compile
* @param {Element} context
* @param {Array} [results]
* @param {Array} [seed] A set of elements to match against
*/
select = Sizzle.select = function (selector, context, results, seed) {
var i, tokens, token, type, find,
compiled = typeof selector === "function" && selector,
match = !seed && tokenize((selector = compiled.selector || selector));
results = results || [];
// Try to minimize operations if there is no seed and only one group
if (match.length === 1) {
// Take a shortcut and set the context if the root selector is an ID
tokens = match[0] = match[0].slice(0);
if (tokens.length > 2 && (token = tokens[0]).type === "ID" &&
support.getById && context.nodeType === 9 && documentIsHTML &&
Expr.relative[tokens[1].type]) {
context = (Expr.find["ID"](token.matches[0].replace(runescape, funescape), context) || [])[0];
if (!context) {
return results;
// Precompiled matchers will still verify ancestry, so step up a level
} else if (compiled) {
context = context.parentNode;
}
selector = selector.slice(tokens.shift().value.length);
}
// Fetch a seed set for right-to-left matching
i = matchExpr["needsContext"].test(selector) ? 0 : tokens.length;
while (i--) {
token = tokens[i];
// Abort if we hit a combinator
if (Expr.relative[(type = token.type)]) {
break;
}
if ((find = Expr.find[type])) {
// Search, expanding context for leading sibling combinators
if ((seed = find(
token.matches[0].replace(runescape, funescape),
rsibling.test(tokens[0].type) && testContext(context.parentNode) || context
))) {
// If seed is empty or no tokens remain, we can return early
tokens.splice(i, 1);
selector = seed.length && toSelector(tokens);
if (!selector) {
push.apply(results, seed);
return results;
}
break;
}
}
}
}
// Compile and execute a filtering function if one is not provided
// Provide `match` to avoid retokenization if we modified the selector above
(compiled || compile(selector, match))(
seed,
context,
!documentIsHTML,
results,
rsibling.test(selector) && testContext(context.parentNode) || context
);
return results;
};
// One-time assignments
// Sort stability
support.sortStable = expando.split("").sort(sortOrder).join("") === expando;
// Support: Chrome 14-35+
// Always assume duplicates if they aren't passed to the comparison function
support.detectDuplicates = !!hasDuplicate;
// Initialize against the default document
setDocument();
// Support: Webkit<537.32 - Safari 6.0.3/Chrome 25 (fixed in Chrome 27)
// Detached nodes confoundingly follow *each other*
support.sortDetached = assert(function (div1) {
// Should return 1, but returns 4 (following)
return div1.compareDocumentPosition(document.createElement("div")) & 1;
});
// Support: IE<8
// Prevent attribute/property "interpolation"
// http://msdn.microsoft.com/en-us/library/ms536429%28VS.85%29.aspx
if (!assert(function (div) {
div.innerHTML = "<a href='#'></a>";
return div.firstChild.getAttribute("href") === "#";
})) {
addHandle("type|href|height|width", function (elem, name, isXML) {
if (!isXML) {
return elem.getAttribute(name, name.toLowerCase() === "type" ? 1 : 2);
}
});
}
// Support: IE<9
// Use defaultValue in place of getAttribute("value")
if (!support.attributes || !assert(function (div) {
div.innerHTML = "<input/>";
div.firstChild.setAttribute("value", "");
return div.firstChild.getAttribute("value") === "";
})) {
addHandle("value", function (elem, name, isXML) {
if (!isXML && elem.nodeName.toLowerCase() === "input") {
return elem.defaultValue;
}
});
}
// Support: IE<9
// Use getAttributeNode to fetch booleans when getAttribute lies
if (!assert(function (div) {
return div.getAttribute("disabled") == null;
})) {
addHandle(booleans, function (elem, name, isXML) {
var val;
if (!isXML) {
return elem[name] === true ? name.toLowerCase() :
(val = elem.getAttributeNode(name)) && val.specified ?
val.value :
null;
}
});
}
return Sizzle;
})(window);