rcomma = new RegExp( "^" + whitespace + "*," + whitespace + "*" ),
rcombinators = new RegExp( "^" + whitespace + "*([\\x20\\t\\r\\n\\f>+~])" + whitespace + "*" ),
rpseudo = new RegExp( pseudos ),
ridentifier = new RegExp( "^" + identifier + "$" ),

matchExpr = {
"ID": new RegExp( "^#(" + characterEncoding + ")" ),
"CLASS": new RegExp( "^\\.(" + characterEncoding + ")" ),
"NAME": new RegExp( "^\\[name=['\"]?(" + 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" ),
// 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" )
},

rsibling = /[\x20\t\r\n\f]*[+~]/,

rnative = /^[^{]+\{\s*\[native code/,

// Easily-parseable/retrievable ID or TAG or CLASS selectors
rquickExpr = /^(?:#([\w-]+)|(\w+)|\.([\w-]+))$/,

rinputs = /^(?:input|select|textarea|button)$/i,
rheader = /^h\d$/i,

rescape = /'|\\/g,
rattributeQuotes = /\=[\x20\t\r\n\f]*([^'"\]]*)[\x20\t\r\n\f]*\]/g,

// CSS escapes http://www.w3.org/TR/CSS21/syndata.html#escaped-characters
runescape = /\\([\da-fA-F]{1,6}[\x20\t\r\n\f]?|.)/g,
funescape = function( _, escaped ) {
var high = "0x" + escaped - 0x10000;
// NaN means non-codepoint
return high !== high ?
escaped :
// BMP codepoint
high < 0 ?
String.fromCharCode( high + 0x10000 ) :
// Supplemental Plane codepoint (surrogate pair)
String.fromCharCode( high >> 10 | 0xD800, high & 0x3FF | 0xDC00 );
};

// Use a stripped-down slice if we can't use a native one
try {
slice.call( preferredDoc.documentElement.childNodes, 0 )[0].nodeType;
} catch ( e ) {
slice = function( i ) {
var elem,
results = [];
while ( (elem = this[i++]) ) {
results.push( elem );
}
return results;
};
}

/**
* For feature detection
* @param {Function} fn The function to test for native support
*/
function isNative( fn ) {
return rnative.test( fn + "" );
}

/**
* 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 cache,
keys = [];

return (cache = function( 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);
});
}

/**
* 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 {
// release memory in IE
div = null;
}
}

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 || [];

if ( !selector || typeof selector !== "string" ) {
return results;
}

if ( (nodeType = context.nodeType) !== 1 && nodeType !== 9 ) {
return [];
}

if ( !documentIsXML && !seed ) {

// Shortcuts
if ( (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 #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, slice.call(context.getElementsByTagName( selector ), 0) );
return results;

// Speed-up: Sizzle(".CLASS")
} else if ( (m = match[3]) && support.getByClassName && context.getElementsByClassName ) {
push.apply( results, slice.call(context.getElementsByClassName( m ), 0) );
return results;
}
}

// QSA path
if ( support.qsa && !rbuggyQSA.test(selector) ) {
old = true;
nid = expando;
newContext = context;
newSelector = nodeType === 9 && 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 ) && context.parentNode || context;
newSelector = groups.join(",");