Function Sizzle

2.0.3/Sizzle.js:186–292

(selector, context, results, seed)

        }

        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 (documentIsHTML && !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, context.getElementsByTagName(selector));
                        return results;

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