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 !== strundefined && 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,
doc = node ? node.ownerDocument || node : preferredDoc,
parent = doc.defaultView;

// 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;

// Support tests
documentIsHTML = !isXML( doc );

// 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", function() {
setDocument();
}, false );
} else if ( parent.attachEvent ) {
parent.attachEvent( "onunload", function() {
setDocument();
});
}
}

/* 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;
});

// Check if getElementsByClassName can be trusted
support.getElementsByClassName = rnative.test( doc.getElementsByClassName ) && assert(function( div ) {
div.innerHTML = "<div class='a'></div><div class='a i'></div>";

// Support: Safari<4
// Catch class over-caching
div.firstChild.className = "i";
// Support: Opera<10
// Catch gEBCN failure to find non-leading classes
return div.getElementsByClassName("i").length === 2;
});

// 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 !== strundefined && 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 !== strundefined && elem.getAttributeNode("id");
return node && node.value === attrId;
};
};
}

// Tag
Expr.find["TAG"] = support.getElementsByTagName ?
function( tag, context ) {
if ( typeof context.getElementsByTagName !== strundefined ) {
return context.getElementsByTagName( tag );
}
} :
function( tag, context ) {
var elem,
tmp = [],
i = 0,
results = context.getElementsByTagName( tag );

// Filter out possible comments
if ( tag === "*" ) {
while ( (elem = results[i++]) ) {
if ( elem.