/* Portions of the Selector class are derived from Jack Slocum's DomQuery,
* part of YUI-Ext version 0.40, distributed under the terms of an MIT-style
* license.  Please see http://www.yui-ext.com/ for more information. */

var Selector = Class.create({
    initialize: function(expression) {
        this.expression = expression.strip();

        if (this.shouldUseSelectorsAPI()) {
            this.mode = 'selectorsAPI';
        } else if (this.shouldUseXPath()) {
            this.mode = 'xpath';
            this.compileXPathMatcher();
        } else {
            this.mode = "normal";
            this.compileMatcher();
        }

    },

    shouldUseXPath: (function() {

        var IS_DESCENDANT_SELECTOR_BUGGY = (function() {
            var isBuggy = false;
            if (document.evaluate && window.XPathResult) {
                var el = document.createElement('div');
                el.innerHTML = '<ul><li></li></ul><div><ul><li></li></ul></div>';

                var xpath = ".//*[local-name()='ul' or local-name()='UL']" +
          "//*[local-name()='li' or local-name()='LI']";

                var result = document.evaluate(xpath, el, null,
          XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);

                isBuggy = (result.snapshotLength !== 2);
                el = null;
            }
            return isBuggy;
        })();

        return function() {
            if (!Prototype.BrowserFeatures.XPath) return false;

            var e = this.expression;

            if (Prototype.Browser.WebKit &&
       (e.include("-of-type") || e.include(":empty")))
                return false;

            if ((/(\[[\w-]*?:|:checked)/).test(e))
                return false;

            if (IS_DESCENDANT_SELECTOR_BUGGY) return false;

            return true;
        }
    })(),

    shouldUseSelectorsAPI: function() {
        if (!Prototype.BrowserFeatures.SelectorsAPI) return false;

        if (Selector.CASE_INSENSITIVE_CLASS_NAMES) return false;

        if (!Selector._div) Selector._div = new Element('div');

        try {
            Selector._div.querySelector(this.expression);
        } catch (e) {
            return false;
        }

        return true;
    },

    compileMatcher: function() {
        var e = this.expression, ps = Selector.patterns, h = Selector.handlers,
        c = Selector.criteria, le, p, m, len = ps.length, name;

        if (Selector._cache[e]) {
            this.matcher = Selector._cache[e];
            return;
        }

        this.matcher = ["this.matcher = function(root) {",
                    "var r = root, h = Selector.handlers, c = false, n;"];

        while (e && le != e && (/\S/).test(e)) {
            le = e;
            for (var i = 0; i < len; i++) {
                p = ps[i].re;
                name = ps[i].name;
                if (m = e.match(p)) {
                    this.matcher.push(Object.isFunction(c[name]) ? c[name](m) :
            new Template(c[name]).evaluate(m));
                    e = e.replace(m[0], '');
                    break;
                }
            }
        }

        this.matcher.push("return h.unique(n);\n}");
        eval(this.matcher.join('\n'));
        Selector._cache[this.expression] = this.matcher;
    },

    compileXPathMatcher: function() {
        var e = this.expression, ps = Selector.patterns,
        x = Selector.xpath, le, m, len = ps.length, name;

        if (Selector._cache[e]) {
            this.xpath = Selector._cache[e]; return;
        }

        this.matcher = ['.//*'];
        while (e && le != e && (/\S/).test(e)) {
            le = e;
            for (var i = 0; i < len; i++) {
                name = ps[i].name;
                if (m = e.match(ps[i].re)) {
                    this.matcher.push(Object.isFunction(x[name]) ? x[name](m) :
            new Template(x[name]).evaluate(m));
                    e = e.replace(m[0], '');
                    break;
                }
            }
        }

        this.xpath = this.matcher.join('');
        Selector._cache[this.expression] = this.xpath;
    },

    findElements: function(root) {
        root = root || document;
        var e = this.expression, results;

        switch (this.mode) {
            case 'selectorsAPI':
                if (root !== document) {
                    var oldId = root.id, id = $(root).identify();
                    id = id.replace(/([\.:])/g, "\\$1");
                    e = "#" + id + " " + e;
                }

                results = $A(root.querySelectorAll(e)).map(Element.extend);
                root.id = oldId;

                return results;
            case 'xpath':
                return document._getElementsByXPath(this.xpath, root);
            default:
                return this.matcher(root);
        }
    },

    match: function(element) {
        this.tokens = [];

        var e = this.expression, ps = Selector.patterns, as = Selector.assertions;
        var le, p, m, len = ps.length, name;

        while (e && le !== e && (/\S/).test(e)) {
            le = e;
            for (var i = 0; i < len; i++) {
                p = ps[i].re;
                name = ps[i].name;
                if (m = e.match(p)) {
                    if (as[name]) {
                        this.tokens.push([name, Object.clone(m)]);
                        e = e.replace(m[0], '');
                    } else {
                        return this.findElements(document).include(element);
                    }
                }
            }
        }

        var match = true, name, matches;
        for (var i = 0, token; token = this.tokens[i]; i++) {
            name = token[0], matches = token[1];
            if (!Selector.assertions[name](element, matches)) {
                match = false; break;
            }
        }

        return match;
    },

    toString: function() {
        return this.expression;
    },

    inspect: function() {
        return "#<Selector:" + this.expression.inspect() + ">";
    }
});

if (Prototype.BrowserFeatures.SelectorsAPI &&
 document.compatMode === 'BackCompat') {
    Selector.CASE_INSENSITIVE_CLASS_NAMES = (function() {
        var div = document.createElement('div'),
     span = document.createElement('span');

        div.id = "prototype_test_id";
        span.className = 'Test';
        div.appendChild(span);
        var isIgnored = (div.querySelector('#prototype_test_id .test') !== null);
        div = span = null;
        return isIgnored;
    })();
}

Object.extend(Selector, {
    _cache: {},

    xpath: {
        descendant: "//*",
        child: "/*",
        adjacent: "/following-sibling::*[1]",
        laterSibling: '/following-sibling::*',
        tagName: function(m) {
            if (m[1] == '*') return '';
            return "[local-name()='" + m[1].toLowerCase() +
             "' or local-name()='" + m[1].toUpperCase() + "']";
        },
        className: "[contains(concat(' ', @class, ' '), ' #{1} ')]",
        id: "[@id='#{1}']",
        attrPresence: function(m) {
            m[1] = m[1].toLowerCase();
            return new Template("[@#{1}]").evaluate(m);
        },
        attr: function(m) {
            m[1] = m[1].toLowerCase();
            m[3] = m[5] || m[6];
            return new Template(Selector.xpath.operators[m[2]]).evaluate(m);
        },
        pseudo: function(m) {
            var h = Selector.xpath.pseudos[m[1]];
            if (!h) return '';
            if (Object.isFunction(h)) return h(m);
            return new Template(Selector.xpath.pseudos[m[1]]).evaluate(m);
        },
        operators: {
            '=': "[@#{1}='#{3}']",
            '!=': "[@#{1}!='#{3}']",
            '^=': "[starts-with(@#{1}, '#{3}')]",
            '$=': "[substring(@#{1}, (string-length(@#{1}) - string-length('#{3}') + 1))='#{3}']",
            '*=': "[contains(@#{1}, '#{3}')]",
            '~=': "[contains(concat(' ', @#{1}, ' '), ' #{3} ')]",
            '|=': "[contains(concat('-', @#{1}, '-'), '-#{3}-')]"
        },
        pseudos: {
            'first-child': '[not(preceding-sibling::*)]',
            'last-child': '[not(following-sibling::*)]',
            'only-child': '[not(preceding-sibling::* or following-sibling::*)]',
            'empty': "[count(*) = 0 and (count(text()) = 0)]",
            'checked': "[@checked]",
            'disabled': "[(@disabled) and (@type!='hidden')]",
            'enabled': "[not(@disabled) and (@type!='hidden')]",
            'not': function(m) {
                var e = m[6], p = Selector.patterns,
            x = Selector.xpath, le, v, len = p.length, name;

                var exclusion = [];
                while (e && le != e && (/\S/).test(e)) {
                    le = e;
                    for (var i = 0; i < len; i++) {
                        name = p[i].name
                        if (m = e.match(p[i].re)) {
                            v = Object.isFunction(x[name]) ? x[name](m) : new Template(x[name]).evaluate(m);
                            exclusion.push("(" + v.substring(1, v.length - 1) + ")");
                            e = e.replace(m[0], '');
                            break;
                        }
                    }
                }
                return "[not(" + exclusion.join(" and ") + ")]";
            },
            'nth-child': function(m) {
                return Selector.xpath.pseudos.nth("(count(./preceding-sibling::*) + 1) ", m);
            },
            'nth-last-child': function(m) {
                return Selector.xpath.pseudos.nth("(count(./following-sibling::*) + 1) ", m);
            },
            'nth-of-type': function(m) {
                return Selector.xpath.pseudos.nth("position() ", m);
            },
            'nth-last-of-type': function(m) {
                return Selector.xpath.pseudos.nth("(last() + 1 - position()) ", m);
            },
            'first-of-type': function(m) {
                m[6] = "1"; return Selector.xpath.pseudos['nth-of-type'](m);
            },
            'last-of-type': function(m) {
                m[6] = "1"; return Selector.xpath.pseudos['nth-last-of-type'](m);
            },
            'only-of-type': function(m) {
                var p = Selector.xpath.pseudos; return p['first-of-type'](m) + p['last-of-type'](m);
            },
            nth: function(fragment, m) {
                var mm, formula = m[6], predicate;
                if (formula == 'even') formula = '2n+0';
                if (formula == 'odd') formula = '2n+1';
                if (mm = formula.match(/^(\d+)$/)) // digit only
                    return '[' + fragment + "= " + mm[1] + ']';
                if (mm = formula.match(/^(-?\d*)?n(([+-])(\d+))?/)) { // an+b
                    if (mm[1] == "-") mm[1] = -1;
                    var a = mm[1] ? Number(mm[1]) : 1;
                    var b = mm[2] ? Number(mm[2]) : 0;
                    predicate = "[((#{fragment} - #{b}) mod #{a} = 0) and " +
          "((#{fragment} - #{b}) div #{a} >= 0)]";
                    return new Template(predicate).evaluate({
                        fragment: fragment, a: a, b: b
                    });
                }
            }
        }
    },

    criteria: {
        tagName: 'n = h.tagName(n, r, "#{1}", c);      c = false;',
        className: 'n = h.className(n, r, "#{1}", c);    c = false;',
        id: 'n = h.id(n, r, "#{1}", c);           c = false;',
        attrPresence: 'n = h.attrPresence(n, r, "#{1}", c); c = false;',
        attr: function(m) {
            m[3] = (m[5] || m[6]);
            return new Template('n = h.attr(n, r, "#{1}", "#{3}", "#{2}", c); c = false;').evaluate(m);
        },
        pseudo: function(m) {
            if (m[6]) m[6] = m[6].replace(/"/g, '\\"');
            return new Template('n = h.pseudo(n, "#{1}", "#{6}", r, c); c = false;').evaluate(m);
        },
        descendant: 'c = "descendant";',
        child: 'c = "child";',
        adjacent: 'c = "adjacent";',
        laterSibling: 'c = "laterSibling";'
    },

    patterns: [
    { name: 'laterSibling', re: /^\s*~\s*/ },
    { name: 'child', re: /^\s*>\s*/ },
    { name: 'adjacent', re: /^\s*\+\s*/ },
    { name: 'descendant', re: /^\s/ },

    { name: 'tagName', re: /^\s*(\*|[\w\-]+)(\b|$)?/ },
    { name: 'id', re: /^#([\w\-\*]+)(\b|$)/ },
    { name: 'className', re: /^\.([\w\-\*]+)(\b|$)/ },
    { name: 'pseudo', re: /^:((first|last|nth|nth-last|only)(-child|-of-type)|empty|checked|(en|dis)abled|not)(\((.*?)\))?(\b|$|(?=\s|[:+~>]))/ },
    { name: 'attrPresence', re: /^\[((?:[\w-]+:)?[\w-]+)\]/ },
    { name: 'attr', re: /\[((?:[\w-]*:)?[\w-]+)\s*(?:([!^$*~|]?=)\s*((['"])([^\4]*?)\4|([^'"][^\]]*?)))?\]/ }
  ],

    assertions: {
        tagName: function(element, matches) {
            return matches[1].toUpperCase() == element.tagName.toUpperCase();
        },

        className: function(element, matches) {
            return Element.hasClassName(element, matches[1]);
        },

        id: function(element, matches) {
            return element.id === matches[1];
        },

        attrPresence: function(element, matches) {
            return Element.hasAttribute(element, matches[1]);
        },

        attr: function(element, matches) {
            var nodeValue = Element.readAttribute(element, matches[1]);
            return nodeValue && Selector.operators[matches[2]](nodeValue, matches[5] || matches[6]);
        }
    },

    handlers: {
        concat: function(a, b) {
            for (var i = 0, node; node = b[i]; i++)
                a.push(node);
            return a;
        },

        mark: function(nodes) {
            var _true = Prototype.emptyFunction;
            for (var i = 0, node; node = nodes[i]; i++)
                node._countedByPrototype = _true;
            return nodes;
        },

        unmark: (function() {

            var PROPERTIES_ATTRIBUTES_MAP = (function() {
                var el = document.createElement('div'),
            isBuggy = false,
            propName = '_countedByPrototype',
            value = 'x'
                el[propName] = value;
                isBuggy = (el.getAttribute(propName) === value);
                el = null;
                return isBuggy;
            })();

            return PROPERTIES_ATTRIBUTES_MAP ?
        function(nodes) {
            for (var i = 0, node; node = nodes[i]; i++)
                node.removeAttribute('_countedByPrototype');
            return nodes;
        } :
        function(nodes) {
            for (var i = 0, node; node = nodes[i]; i++)
                node._countedByPrototype = void 0;
            return nodes;
        }
        })(),

        index: function(parentNode, reverse, ofType) {
            parentNode._countedByPrototype = Prototype.emptyFunction;
            if (reverse) {
                for (var nodes = parentNode.childNodes, i = nodes.length - 1, j = 1; i >= 0; i--) {
                    var node = nodes[i];
                    if (node.nodeType == 1 && (!ofType || node._countedByPrototype)) node.nodeIndex = j++;
                }
            } else {
                for (var i = 0, j = 1, nodes = parentNode.childNodes; node = nodes[i]; i++)
                    if (node.nodeType == 1 && (!ofType || node._countedByPrototype)) node.nodeIndex = j++;
            }
        },

        unique: function(nodes) {
            if (nodes.length == 0) return nodes;
            var results = [], n;
            for (var i = 0, l = nodes.length; i < l; i++)
                if (typeof (n = nodes[i])._countedByPrototype == 'undefined') {
                n._countedByPrototype = Prototype.emptyFunction;
                results.push(Element.extend(n));
            }
            return Selector.handlers.unmark(results);
        },

        descendant: function(nodes) {
            var h = Selector.handlers;
            for (var i = 0, results = [], node; node = nodes[i]; i++)
                h.concat(results, node.getElementsByTagName('*'));
            return results;
        },

        child: function(nodes) {
            var h = Selector.handlers;
            for (var i = 0, results = [], node; node = nodes[i]; i++) {
                for (var j = 0, child; child = node.childNodes[j]; j++)
                    if (child.nodeType == 1 && child.tagName != '!') results.push(child);
            }
            return results;
        },

        adjacent: function(nodes) {
            for (var i = 0, results = [], node; node = nodes[i]; i++) {
                var next = this.nextElementSibling(node);
                if (next) results.push(next);
            }
            return results;
        },

        laterSibling: function(nodes) {
            var h = Selector.handlers;
            for (var i = 0, results = [], node; node = nodes[i]; i++)
                h.concat(results, Element.nextSiblings(node));
            return results;
        },

        nextElementSibling: function(node) {
            while (node = node.nextSibling)
                if (node.nodeType == 1) return node;
            return null;
        },

        previousElementSibling: function(node) {
            while (node = node.previousSibling)
                if (node.nodeType == 1) return node;
            return null;
        },

        tagName: function(nodes, root, tagName, combinator) {
            var uTagName = tagName.toUpperCase();
            var results = [], h = Selector.handlers;
            if (nodes) {
                if (combinator) {
                    if (combinator == "descendant") {
                        for (var i = 0, node; node = nodes[i]; i++)
                            h.concat(results, node.getElementsByTagName(tagName));
                        return results;
                    } else nodes = this[combinator](nodes);
                    if (tagName == "*") return nodes;
                }
                for (var i = 0, node; node = nodes[i]; i++)
                    if (node.tagName.toUpperCase() === uTagName) results.push(node);
                return results;
            } else return root.getElementsByTagName(tagName);
        },

        id: function(nodes, root, id, combinator) {
            var targetNode = $(id), h = Selector.handlers;

            if (root == document) {
                if (!targetNode) return [];
                if (!nodes) return [targetNode];
            } else {
                if (!root.sourceIndex || root.sourceIndex < 1) {
                    var nodes = root.getElementsByTagName('*');
                    for (var j = 0, node; node = nodes[j]; j++) {
                        if (node.id === id) return [node];
                    }
                }
            }

            if (nodes) {
                if (combinator) {
                    if (combinator == 'child') {
                        for (var i = 0, node; node = nodes[i]; i++)
                            if (targetNode.parentNode == node) return [targetNode];
                    } else if (combinator == 'descendant') {
                        for (var i = 0, node; node = nodes[i]; i++)
                            if (Element.descendantOf(targetNode, node)) return [targetNode];
                    } else if (combinator == 'adjacent') {
                        for (var i = 0, node; node = nodes[i]; i++)
                            if (Selector.handlers.previousElementSibling(targetNode) == node)
                            return [targetNode];
                    } else nodes = h[combinator](nodes);
                }
                for (var i = 0, node; node = nodes[i]; i++)
                    if (node == targetNode) return [targetNode];
                return [];
            }
            return (targetNode && Element.descendantOf(targetNode, root)) ? [targetNode] : [];
        },

        className: function(nodes, root, className, combinator) {
            if (nodes && combinator) nodes = this[combinator](nodes);
            return Selector.handlers.byClassName(nodes, root, className);
        },

        byClassName: function(nodes, root, className) {
            if (!nodes) nodes = Selector.handlers.descendant([root]);
            var needle = ' ' + className + ' ';
            for (var i = 0, results = [], node, nodeClassName; node = nodes[i]; i++) {
                nodeClassName = node.className;
                if (nodeClassName.length == 0) continue;
                if (nodeClassName == className || (' ' + nodeClassName + ' ').include(needle))
                    results.push(node);
            }
            return results;
        },

        attrPresence: function(nodes, root, attr, combinator) {
            if (!nodes) nodes = root.getElementsByTagName("*");
            if (nodes && combinator) nodes = this[combinator](nodes);
            var results = [];
            for (var i = 0, node; node = nodes[i]; i++)
                if (Element.hasAttribute(node, attr)) results.push(node);
            return results;
        },

        attr: function(nodes, root, attr, value, operator, combinator) {
            if (!nodes) nodes = root.getElementsByTagName("*");
            if (nodes && combinator) nodes = this[combinator](nodes);
            var handler = Selector.operators[operator], results = [];
            for (var i = 0, node; node = nodes[i]; i++) {
                var nodeValue = Element.readAttribute(node, attr);
                if (nodeValue === null) continue;
                if (handler(nodeValue, value)) results.push(node);
            }
            return results;
        },

        pseudo: function(nodes, name, value, root, combinator) {
            if (nodes && combinator) nodes = this[combinator](nodes);
            if (!nodes) nodes = root.getElementsByTagName("*");
            return Selector.pseudos[name](nodes, value, root);
        }
    },

    pseudos: {
        'first-child': function(nodes, value, root) {
            for (var i = 0, results = [], node; node = nodes[i]; i++) {
                if (Selector.handlers.previousElementSibling(node)) continue;
                results.push(node);
            }
            return results;
        },
        'last-child': function(nodes, value, root) {
            for (var i = 0, results = [], node; node = nodes[i]; i++) {
                if (Selector.handlers.nextElementSibling(node)) continue;
                results.push(node);
            }
            return results;
        },
        'only-child': function(nodes, value, root) {
            var h = Selector.handlers;
            for (var i = 0, results = [], node; node = nodes[i]; i++)
                if (!h.previousElementSibling(node) && !h.nextElementSibling(node))
                results.push(node);
            return results;
        },
        'nth-child': function(nodes, formula, root) {
            return Selector.pseudos.nth(nodes, formula, root);
        },
        'nth-last-child': function(nodes, formula, root) {
            return Selector.pseudos.nth(nodes, formula, root, true);
        },
        'nth-of-type': function(nodes, formula, root) {
            return Selector.pseudos.nth(nodes, formula, root, false, true);
        },
        'nth-last-of-type': function(nodes, formula, root) {
            return Selector.pseudos.nth(nodes, formula, root, true, true);
        },
        'first-of-type': function(nodes, formula, root) {
            return Selector.pseudos.nth(nodes, "1", root, false, true);
        },
        'last-of-type': function(nodes, formula, root) {
            return Selector.pseudos.nth(nodes, "1", root, true, true);
        },
        'only-of-type': function(nodes, formula, root) {
            var p = Selector.pseudos;
            return p['last-of-type'](p['first-of-type'](nodes, formula, root), formula, root);
        },

        getIndices: function(a, b, total) {
            if (a == 0) return b > 0 ? [b] : [];
            return $R(1, total).inject([], function(memo, i) {
                if (0 == (i - b) % a && (i - b) / a >= 0) memo.push(i);
                return memo;
            });
        },

        nth: function(nodes, formula, root, reverse, ofType) {
            if (nodes.length == 0) return [];
            if (formula == 'even') formula = '2n+0';
            if (formula == 'odd') formula = '2n+1';
            var h = Selector.handlers, results = [], indexed = [], m;
            h.mark(nodes);
            for (var i = 0, node; node = nodes[i]; i++) {
                if (!node.parentNode._countedByPrototype) {
                    h.index(node.parentNode, reverse, ofType);
                    indexed.push(node.parentNode);
                }
            }
            if (formula.match(/^\d+$/)) { // just a number
                formula = Number(formula);
                for (var i = 0, node; node = nodes[i]; i++)
                    if (node.nodeIndex == formula) results.push(node);
            } else if (m = formula.match(/^(-?\d*)?n(([+-])(\d+))?/)) { // an+b
                if (m[1] == "-") m[1] = -1;
                var a = m[1] ? Number(m[1]) : 1;
                var b = m[2] ? Number(m[2]) : 0;
                var indices = Selector.pseudos.getIndices(a, b, nodes.length);
                for (var i = 0, node, l = indices.length; node = nodes[i]; i++) {
                    for (var j = 0; j < l; j++)
                        if (node.nodeIndex == indices[j]) results.push(node);
                }
            }
            h.unmark(nodes);
            h.unmark(indexed);
            return results;
        },

        'empty': function(nodes, value, root) {
            for (var i = 0, results = [], node; node = nodes[i]; i++) {
                if (node.tagName == '!' || node.firstChild) continue;
                results.push(node);
            }
            return results;
        },

        'not': function(nodes, selector, root) {
            var h = Selector.handlers, selectorType, m;
            var exclusions = new Selector(selector).findElements(root);
            h.mark(exclusions);
            for (var i = 0, results = [], node; node = nodes[i]; i++)
                if (!node._countedByPrototype) results.push(node);
            h.unmark(exclusions);
            return results;
        },

        'enabled': function(nodes, value, root) {
            for (var i = 0, results = [], node; node = nodes[i]; i++)
                if (!node.disabled && (!node.type || node.type !== 'hidden'))
                results.push(node);
            return results;
        },

        'disabled': function(nodes, value, root) {
            for (var i = 0, results = [], node; node = nodes[i]; i++)
                if (node.disabled) results.push(node);
            return results;
        },

        'checked': function(nodes, value, root) {
            for (var i = 0, results = [], node; node = nodes[i]; i++)
                if (node.checked) results.push(node);
            return results;
        }
    },

    operators: {
        '=': function(nv, v) { return nv == v; },
        '!=': function(nv, v) { return nv != v; },
        '^=': function(nv, v) { return nv == v || nv && nv.startsWith(v); },
        '$=': function(nv, v) { return nv == v || nv && nv.endsWith(v); },
        '*=': function(nv, v) { return nv == v || nv && nv.include(v); },
        '~=': function(nv, v) { return (' ' + nv + ' ').include(' ' + v + ' '); },
        '|=': function(nv, v) {
            return ('-' + (nv || "").toUpperCase() +
     '-').include('-' + (v || "").toUpperCase() + '-');
        }
    },

    split: function(expression) {
        var expressions = [];
        expression.scan(/(([\w#:.~>+()\s-]+|\*|\[.*?\])+)\s*(,|$)/, function(m) {
            expressions.push(m[1].strip());
        });
        return expressions;
    },

    matchElements: function(elements, expression) {
        var matches = $$(expression), h = Selector.handlers;
        h.mark(matches);
        for (var i = 0, results = [], element; element = elements[i]; i++)
            if (element._countedByPrototype) results.push(element);
        h.unmark(matches);
        return results;
    },

    findElement: function(elements, expression, index) {
        if (Object.isNumber(expression)) {
            index = expression; expression = false;
        }
        return Selector.matchElements(elements, expression || '*')[index || 0];
    },

    findChildElements: function(element, expressions) {
        expressions = Selector.split(expressions.join(','));
        var results = [], h = Selector.handlers;
        for (var i = 0, l = expressions.length, selector; i < l; i++) {
            selector = new Selector(expressions[i].strip());
            h.concat(results, selector.findElements(element));
        }
        return (l > 1) ? h.unique(results) : results;
    }
});

if (Prototype.Browser.IE) {
    Object.extend(Selector.handlers, {
        concat: function(a, b) {
            for (var i = 0, node; node = b[i]; i++)
                if (node.tagName !== "!") a.push(node);
            return a;
        }
    });
}

function $$() {
    return Selector.findChildElements(document, $A(arguments));
}

var Form = {
    reset: function(form) {
        form = $(form);
        form.reset();
        return form;
    },

    serializeElements: function(elements, options) {
        if (typeof options != 'object') options = { hash: !!options };
        else if (Object.isUndefined(options.hash)) options.hash = true;
        var key, value, submitted = false, submit = options.submit;

        var data = elements.inject({}, function(result, element) {
            if (!element.disabled && element.name) {
                key = element.name; value = $(element).getValue();
                if (value != null && element.type != 'file' && (element.type != 'submit' || (!submitted &&
            submit !== false && (!submit || key == submit) && (submitted = true)))) {
                    if (key in result) {
                        if (!Object.isArray(result[key])) result[key] = [result[key]];
                        result[key].push(value);
                    }
                    else result[key] = value;
                }
            }
            return result;
        });

        return options.hash ? data : Object.toQueryString(data);
    }
};

Form.Methods = {
    serialize: function(form, options) {
        return Form.serializeElements(Form.getElements(form), options);
    },

    getElements: function(form) {
        var elements = $(form).getElementsByTagName('*'),
        element,
        arr = [],
        serializers = Form.Element.Serializers;
        for (var i = 0; element = elements[i]; i++) {
            arr.push(element);
        }
        return arr.inject([], function(elements, child) {
            if (serializers[child.tagName.toLowerCase()])
                elements.push(Element.extend(child));
            return elements;
        })
    },

    getInputs: function(form, typeName, name) {
        form = $(form);
        var inputs = form.getElementsByTagName('input');

        if (!typeName && !name) return $A(inputs).map(Element.extend);

        for (var i = 0, matchingInputs = [], length = inputs.length; i < length; i++) {
            var input = inputs[i];
            if ((typeName && input.type != typeName) || (name && input.name != name))
                continue;
            matchingInputs.push(Element.extend(input));
        }

        return matchingInputs;
    },

    disable: function(form) {
        form = $(form);
        Form.getElements(form).invoke('disable');
        return form;
    },

    enable: function(form) {
        form = $(form);
        Form.getElements(form).invoke('enable');
        return form;
    },

    findFirstElement: function(form) {
        var elements = $(form).getElements().findAll(function(element) {
            return 'hidden' != element.type && !element.disabled;
        });
        var firstByIndex = elements.findAll(function(element) {
            return element.hasAttribute('tabIndex') && element.tabIndex >= 0;
        }).sortBy(function(element) { return element.tabIndex }).first();

        return firstByIndex ? firstByIndex : elements.find(function(element) {
            return /^(?:input|select|textarea)$/i.test(element.tagName);
        });
    },

    focusFirstElement: function(form) {
        form = $(form);
        form.findFirstElement().activate();
        return form;
    },

    request: function(form, options) {
        form = $(form), options = Object.clone(options || {});

        var params = options.parameters, action = form.readAttribute('action') || '';
        if (action.blank()) action = window.location.href;
        options.parameters = form.serialize(true);

        if (params) {
            if (Object.isString(params)) params = params.toQueryParams();
            Object.extend(options.parameters, params);
        }

        if (form.hasAttribute('method') && !options.method)
            options.method = form.method;

        return new Ajax.Request(action, options);
    }
};

/*--------------------------------------------------------------------------*/


Form.Element = {
    focus: function(element) {
        $(element).focus();
        return element;
    },

    select: function(element) {
        $(element).select();
        return element;
    }
};

Form.Element.Methods = {

    serialize: function(element) {
        element = $(element);
        if (!element.disabled && element.name) {
            var value = element.getValue();
            if (value != undefined) {
                var pair = {};
                pair[element.name] = value;
                return Object.toQueryString(pair);
            }
        }
        return '';
    },

    getValue: function(element) {
        element = $(element);
        var method = element.tagName.toLowerCase();
        return Form.Element.Serializers[method](element);
    },

    setValue: function(element, value) {
        element = $(element);
        var method = element.tagName.toLowerCase();
        Form.Element.Serializers[method](element, value);
        return element;
    },

    clear: function(element) {
        $(element).value = '';
        return element;
    },

    present: function(element) {
        return $(element).value != '';
    },

    activate: function(element) {
        element = $(element);
        try {
            element.focus();
            if (element.select && (element.tagName.toLowerCase() != 'input' ||
          !(/^(?:button|reset|submit)$/i.test(element.type))))
                element.select();
        } catch (e) { }
        return element;
    },

    disable: function(element) {
        element = $(element);
        element.disabled = true;
        return element;
    },

    enable: function(element) {
        element = $(element);
        element.disabled = false;
        return element;
    }
};

/*--------------------------------------------------------------------------*/

var Field = Form.Element;

var $F = Form.Element.Methods.getValue;

/*--------------------------------------------------------------------------*/

Form.Element.Serializers = {
    input: function(element, value) {
        switch (element.type.toLowerCase()) {
            case 'checkbox':
            case 'radio':
                return Form.Element.Serializers.inputSelector(element, value);
            default:
                return Form.Element.Serializers.textarea(element, value);
        }
    },

    inputSelector: function(element, value) {
        if (Object.isUndefined(value)) return element.checked ? element.value : null;
        else element.checked = !!value;
    },

    textarea: function(element, value) {
        if (Object.isUndefined(value)) return element.value;
        else element.value = value;
    },

    select: function(element, value) {
        if (Object.isUndefined(value))
            return this[element.type == 'select-one' ?
        'selectOne' : 'selectMany'](element);
        else {
            var opt, currentValue, single = !Object.isArray(value);
            for (var i = 0, length = element.length; i < length; i++) {
                opt = element.options[i];
                currentValue = this.optionValue(opt);
                if (single) {
                    if (currentValue == value) {
                        opt.selected = true;
                        return;
                    }
                }
                else opt.selected = value.include(currentValue);
            }
        }
    },

    selectOne: function(element) {
        var index = element.selectedIndex;
        return index >= 0 ? this.optionValue(element.options[index]) : null;
    },

    selectMany: function(element) {
        var values, length = element.length;
        if (!length) return null;

        for (var i = 0, values = []; i < length; i++) {
            var opt = element.options[i];
            if (opt.selected) values.push(this.optionValue(opt));
        }
        return values;
    },

    optionValue: function(opt) {
        return Element.extend(opt).hasAttribute('value') ? opt.value : opt.text;
    }
};

/*--------------------------------------------------------------------------*/


Abstract.TimedObserver = Class.create(PeriodicalExecuter, {
    initialize: function($super, element, frequency, callback) {
        $super(callback, frequency);
        this.element = $(element);
        this.lastValue = this.getValue();
    },

    execute: function() {
        var value = this.getValue();
        if (Object.isString(this.lastValue) && Object.isString(value) ?
        this.lastValue != value : String(this.lastValue) != String(value)) {
            this.callback(this.element, value);
            this.lastValue = value;
        }
    }
});

Form.Element.Observer = Class.create(Abstract.TimedObserver, {
    getValue: function() {
        return Form.Element.getValue(this.element);
    }
});

Form.Observer = Class.create(Abstract.TimedObserver, {
    getValue: function() {
        return Form.serialize(this.element);
    }
});

/*--------------------------------------------------------------------------*/

Abstract.EventObserver = Class.create({
    initialize: function(element, callback) {
        this.element = $(element);
        this.callback = callback;

        this.lastValue = this.getValue();
        if (this.element.tagName.toLowerCase() == 'form')
            this.registerFormCallbacks();
        else
            this.registerCallback(this.element);
    },

    onElementEvent: function() {
        var value = this.getValue();
        if (this.lastValue != value) {
            this.callback(this.element, value);
            this.lastValue = value;
        }
    },

    registerFormCallbacks: function() {
        Form.getElements(this.element).each(this.registerCallback, this);
    },

    registerCallback: function(element) {
        if (element.type) {
            switch (element.type.toLowerCase()) {
                case 'checkbox':
                case 'radio':
                    Event.observe(element, 'click', this.onElementEvent.bind(this));
                    break;
                default:
                    Event.observe(element, 'change', this.onElementEvent.bind(this));
                    break;
            }
        }
    }
});

Form.Element.EventObserver = Class.create(Abstract.EventObserver, {
    getValue: function() {
        return Form.Element.getValue(this.element);
    }
});

Form.EventObserver = Class.create(Abstract.EventObserver, {
    getValue: function() {
        return Form.serialize(this.element);
    }
});
(function() {

    var Event = {
        KEY_BACKSPACE: 8,
        KEY_TAB: 9,
        KEY_RETURN: 13,
        KEY_ESC: 27,
        KEY_LEFT: 37,
        KEY_UP: 38,
        KEY_RIGHT: 39,
        KEY_DOWN: 40,
        KEY_DELETE: 46,
        KEY_HOME: 36,
        KEY_END: 35,
        KEY_PAGEUP: 33,
        KEY_PAGEDOWN: 34,
        KEY_INSERT: 45,

        cache: {}
    };

    var docEl = document.documentElement;
    var MOUSEENTER_MOUSELEAVE_EVENTS_SUPPORTED = 'onmouseenter' in docEl
    && 'onmouseleave' in docEl;

    var _isButton;
    if (Prototype.Browser.IE) {
        var buttonMap = { 0: 1, 1: 4, 2: 2 };
        _isButton = function(event, code) {
            return event.button === buttonMap[code];
        };
    } else if (Prototype.Browser.WebKit) {
        _isButton = function(event, code) {
            switch (code) {
                case 0: return event.which == 1 && !event.metaKey;
                case 1: return event.which == 1 && event.metaKey;
                default: return false;
            }
        };
    } else {
        _isButton = function(event, code) {
            return event.which ? (event.which === code + 1) : (event.button === code);
        };
    }

    function isLeftClick(event) { return _isButton(event, 0) }

    function isMiddleClick(event) { return _isButton(event, 1) }

    function isRightClick(event) { return _isButton(event, 2) }

    function element(event) {
        event = Event.extend(event);

        var node = event.target, type = event.type,
     currentTarget = event.currentTarget;

        if (currentTarget && currentTarget.tagName) {
            if (type === 'load' || type === 'error' ||
        (type === 'click' && currentTarget.tagName.toLowerCase() === 'input'
          && currentTarget.type === 'radio'))
                node = currentTarget;
        }

        if (node.nodeType == Node.TEXT_NODE)
            node = node.parentNode;

        return Element.extend(node);
    }

    function findElement(event, expression) {
        var element = Event.element(event);
        if (!expression) return element;
        var elements = [element].concat(element.ancestors());
        return Selector.findElement(elements, expression, 0);
    }

    function pointer(event) {
        return { x: pointerX(event), y: pointerY(event) };
    }

    function pointerX(event) {
        var docElement = document.documentElement,
     body = document.body || { scrollLeft: 0 };

        return event.pageX || (event.clientX +
      (docElement.scrollLeft || body.scrollLeft) -
      (docElement.clientLeft || 0));
    }

    function pointerY(event) {
        var docElement = document.documentElement,
     body = document.body || { scrollTop: 0 };

        return event.pageY || (event.clientY +
       (docElement.scrollTop || body.scrollTop) -
       (docElement.clientTop || 0));
    }


    function stop(event) {
        Event.extend(event);
        event.preventDefault();
        event.stopPropagation();

        event.stopped = true;
    }

    Event.Methods = {
        isLeftClick: isLeftClick,
        isMiddleClick: isMiddleClick,
        isRightClick: isRightClick,

        element: element,
        findElement: findElement,

        pointer: pointer,
        pointerX: pointerX,
        pointerY: pointerY,

        stop: stop
    };


    var methods = Object.keys(Event.Methods).inject({}, function(m, name) {
        m[name] = Event.Methods[name].methodize();
        return m;
    });

    if (Prototype.Browser.IE) {
        function _relatedTarget(event) {
            var element;
            switch (event.type) {
                case 'mouseover': element = event.fromElement; break;
                case 'mouseout': element = event.toElement; break;
                default: return null;
            }
            return Element.extend(element);
        }

        Object.extend(methods, {
            stopPropagation: function() { this.cancelBubble = true },
            preventDefault: function() { this.returnValue = false },
            inspect: function() { return '[object Event]' }
        });

        Event.extend = function(event, element) {
            if (!event) return false;
            if (event._extendedByPrototype) return event;

            event._extendedByPrototype = Prototype.emptyFunction;
            var pointer = Event.pointer(event);

            Object.extend(event, {
                target: event.srcElement || element,
                relatedTarget: _relatedTarget(event),
                pageX: pointer.x,
                pageY: pointer.y
            });

            return Object.extend(event, methods);
        };
    } else {
        Event.prototype = window.Event.prototype || document.createEvent('HTMLEvents').__proto__;
        Object.extend(Event.prototype, methods);
        Event.extend = Prototype.K;
    }

    function _createResponder(element, eventName, handler) {
        var registry = Element.retrieve(element, 'prototype_event_registry');

        if (Object.isUndefined(registry)) {
            CACHE.push(element);
            registry = Element.retrieve(element, 'prototype_event_registry', $H());
        }

        var respondersForEvent = registry.get(eventName);
        if (Object.isUndefined(respondersForEvent)) {
            respondersForEvent = [];
            registry.set(eventName, respondersForEvent);
        }

        if (respondersForEvent.pluck('handler').include(handler)) return false;

        var responder;
        if (eventName.include(":")) {
            responder = function(event) {
                if (Object.isUndefined(event.eventName))
                    return false;

                if (event.eventName !== eventName)
                    return false;

                Event.extend(event, element);
                handler.call(element, event);
            };
        } else {
            if (!MOUSEENTER_MOUSELEAVE_EVENTS_SUPPORTED &&
       (eventName === "mouseenter" || eventName === "mouseleave")) {
                if (eventName === "mouseenter" || eventName === "mouseleave") {
                    responder = function(event) {
                        Event.extend(event, element);

                        var parent = event.relatedTarget;
                        while (parent && parent !== element) {
                            try { parent = parent.parentNode; }
                            catch (e) { parent = element; }
                        }

                        if (parent === element) return;

                        handler.call(element, event);
                    };
                }
            } else {
                responder = function(event) {
                    Event.extend(event, element);
                    handler.call(element, event);
                };
            }
        }

        responder.handler = handler;
        respondersForEvent.push(responder);
        return responder;
    }

    function _destroyCache() {
        for (var i = 0, length = CACHE.length; i < length; i++) {
            Event.stopObserving(CACHE[i]);
            CACHE[i] = null;
        }
    }

    var CACHE = [];

    if (Prototype.Browser.IE)
        window.attachEvent('onunload', _destroyCache);

    if (Prototype.Browser.WebKit)
        window.addEventListener('unload', Prototype.emptyFunction, false);


    var _getDOMEventName = Prototype.K;

    if (!MOUSEENTER_MOUSELEAVE_EVENTS_SUPPORTED) {
        _getDOMEventName = function(eventName) {
            var translations = { mouseenter: "mouseover", mouseleave: "mouseout" };
            return eventName in translations ? translations[eventName] : eventName;
        };
    }

    function observe(element, eventName, handler) {
        element = $(element);

        var responder = _createResponder(element, eventName, handler);

        if (!responder) return element;

        if (eventName.include(':')) {
            if (element.addEventListener)
                element.addEventListener("dataavailable", responder, false);
            else {
                element.attachEvent("ondataavailable", responder);
                element.attachEvent("onfilterchange", responder);
            }
        } else {
            var actualEventName = _getDOMEventName(eventName);

            if (element.addEventListener)
                element.addEventListener(actualEventName, responder, false);
            else
                element.attachEvent("on" + actualEventName, responder);
        }

        return element;
    }

    function stopObserving(element, eventName, handler) {
        element = $(element);

        var registry = Element.retrieve(element, 'prototype_event_registry');

        if (Object.isUndefined(registry)) return element;

        if (eventName && !handler) {
            var responders = registry.get(eventName);

            if (Object.isUndefined(responders)) return element;

            responders.each(function(r) {
                Element.stopObserving(element, eventName, r.handler);
            });
            return element;
        } else if (!eventName) {
            registry.each(function(pair) {
                var eventName = pair.key, responders = pair.value;

                responders.each(function(r) {
                    Element.stopObserving(element, eventName, r.handler);
                });
            });
            return element;
        }

        var responders = registry.get(eventName);

        if (!responders) return;

        var responder = responders.find(function(r) { return r.handler === handler; });
        if (!responder) return element;

        var actualEventName = _getDOMEventName(eventName);

        if (eventName.include(':')) {
            if (element.removeEventListener)
                element.removeEventListener("dataavailable", responder, false);
            else {
                element.detachEvent("ondataavailable", responder);
                element.detachEvent("onfilterchange", responder);
            }
        } else {
            if (element.removeEventListener)
                element.removeEventListener(actualEventName, responder, false);
            else
                element.detachEvent('on' + actualEventName, responder);
        }

        registry.set(eventName, responders.without(responder));

        return element;
    }

    function fire(element, eventName, memo, bubble) {
        element = $(element);

        if (Object.isUndefined(bubble))
            bubble = true;

        if (element == document && document.createEvent && !element.dispatchEvent)
            element = document.documentElement;

        var event;
        if (document.createEvent) {
            event = document.createEvent('HTMLEvents');
            event.initEvent('dataavailable', true, true);
        } else {
            event = document.createEventObject();
            event.eventType = bubble ? 'ondataavailable' : 'onfilterchange';
        }

        event.eventName = eventName;
        event.memo = memo || {};

        if (document.createEvent)
            element.dispatchEvent(event);
        else
            element.fireEvent(event.eventType, event);

        return Event.extend(event);
    }


    Object.extend(Event, Event.Methods);

    Object.extend(Event, {
        fire: fire,
        observe: observe,
        stopObserving: stopObserving
    });

    Element.addMethods({
        fire: fire,

        observe: observe,

        stopObserving: stopObserving
    });

    Object.extend(document, {
        fire: fire.methodize(),

        observe: observe.methodize(),

        stopObserving: stopObserving.methodize(),

        loaded: false
    });

    if (window.Event) Object.extend(window.Event, Event);
    else window.Event = Event;
})();

(function() {
    /* Support for the DOMContentLoaded event is based on work by Dan Webb,
    Matthias Miller, Dean Edwards, John Resig, and Diego Perini. */

    var timer;

    function fireContentLoadedEvent() {
        if (document.loaded) return;
        if (timer) window.clearTimeout(timer);
        document.loaded = true;
        document.fire('dom:loaded');
    }

    function checkReadyState() {
        if (document.readyState === 'complete') {
            document.stopObserving('readystatechange', checkReadyState);
            fireContentLoadedEvent();
        }
    }

    function pollDoScroll() {
        try { document.documentElement.doScroll('left'); }
        catch (e) {
            timer = pollDoScroll.defer();
            return;
        }
        fireContentLoadedEvent();
    }

    if (document.addEventListener) {
        document.addEventListener('DOMContentLoaded', fireContentLoadedEvent, false);
    } else {
        document.observe('readystatechange', checkReadyState);
        if (window == top)
            timer = pollDoScroll.defer();
    }

    Event.observe(window, 'load', fireContentLoadedEvent);
})();

Element.addMethods();

/*------------------------------- DEPRECATED -------------------------------*/

Hash.toQueryString = Object.toQueryString;

var Toggle = { display: Element.toggle };

Element.Methods.childOf = Element.Methods.descendantOf;

var Insertion = {
    Before: function(element, content) {
        return Element.insert(element, { before: content });
    },

    Top: function(element, content) {
        return Element.insert(element, { top: content });
    },

    Bottom: function(element, content) {
        return Element.insert(element, { bottom: content });
    },

    After: function(element, content) {
        return Element.insert(element, { after: content });
    }
};

var $continue = new Error('"throw $continue" is deprecated, use "return" instead');

var Position = {
    includeScrollOffsets: false,

    prepare: function() {
        this.deltaX = window.pageXOffset
                || document.documentElement.scrollLeft
                || document.body.scrollLeft
                || 0;
        this.deltaY = window.pageYOffset
                || document.documentElement.scrollTop
                || document.body.scrollTop
                || 0;
    },

    within: function(element, x, y) {
        if (this.includeScrollOffsets)
            return this.withinIncludingScrolloffsets(element, x, y);
        this.xcomp = x;
        this.ycomp = y;
        this.offset = Element.cumulativeOffset(element);

        return (y >= this.offset[1] &&
            y < this.offset[1] + element.offsetHeight &&
            x >= this.offset[0] &&
            x < this.offset[0] + element.offsetWidth);
    },

    withinIncludingScrolloffsets: function(element, x, y) {
        var offsetcache = Element.cumulativeScrollOffset(element);

        this.xcomp = x + offsetcache[0] - this.deltaX;
        this.ycomp = y + offsetcache[1] - this.deltaY;
        this.offset = Element.cumulativeOffset(element);

        return (this.ycomp >= this.offset[1] &&
            this.ycomp < this.offset[1] + element.offsetHeight &&
            this.xcomp >= this.offset[0] &&
            this.xcomp < this.offset[0] + element.offsetWidth);
    },

    overlap: function(mode, element) {
        if (!mode) return 0;
        if (mode == 'vertical')
            return ((this.offset[1] + element.offsetHeight) - this.ycomp) /
        element.offsetHeight;
        if (mode == 'horizontal')
            return ((this.offset[0] + element.offsetWidth) - this.xcomp) /
        element.offsetWidth;
    },


    cumulativeOffset: Element.Methods.cumulativeOffset,

    positionedOffset: Element.Methods.positionedOffset,

    absolutize: function(element) {
        Position.prepare();
        return Element.absolutize(element);
    },

    relativize: function(element) {
        Position.prepare();
        return Element.relativize(element);
    },

    realOffset: Element.Methods.cumulativeScrollOffset,

    offsetParent: Element.Methods.getOffsetParent,

    page: Element.Methods.viewportOffset,

    clone: function(source, target, options) {
        options = options || {};
        return Element.clonePosition(target, source, options);
    }
};

/*--------------------------------------------------------------------------*/

if (!document.getElementsByClassName) document.getElementsByClassName = function(instanceMethods) {
    function iter(name) {
        return name.blank() ? null : "[contains(concat(' ', @class, ' '), ' " + name + " ')]";
    }

    instanceMethods.getElementsByClassName = Prototype.BrowserFeatures.XPath ?
  function(element, className) {
      className = className.toString().strip();
      var cond = /\s/.test(className) ? $w(className).map(iter).join('') : iter(className);
      return cond ? document._getElementsByXPath('.//*' + cond, element) : [];
  } : function(element, className) {
      className = className.toString().strip();
      var elements = [], classNames = (/\s/.test(className) ? $w(className) : null);
      if (!classNames && !className) return elements;

      var nodes = $(element).getElementsByTagName('*');
      className = ' ' + className + ' ';

      for (var i = 0, child, cn; child = nodes[i]; i++) {
          if (child.className && (cn = ' ' + child.className + ' ') && (cn.include(className) ||
          (classNames && classNames.all(function(name) {
              return !name.toString().blank() && cn.include(' ' + name + ' ');
          }))))
              elements.push(Element.extend(child));
      }
      return elements;
  };

    return function(className, parentElement) {
        return $(parentElement || document.body).getElementsByClassName(className);
    };
} (Element.Methods);

/*--------------------------------------------------------------------------*/

Element.ClassNames = Class.create();
Element.ClassNames.prototype = {
    initialize: function(element) {
        this.element = $(element);
    },

    _each: function(iterator) {
        this.element.className.split(/\s+/).select(function(name) {
            return name.length > 0;
        })._each(iterator);
    },

    set: function(className) {
        this.element.className = className;
    },

    add: function(classNameToAdd) {
        if (this.include(classNameToAdd)) return;
        this.set($A(this).concat(classNameToAdd).join(' '));
    },

    remove: function(classNameToRemove) {
        if (!this.include(classNameToRemove)) return;
        this.set($A(this).without(classNameToRemove).join(' '));
    },

    toString: function() {
        return $A(this).join(' ');
    }
};