XPath

xpath Function
目前為 2017-04-21 提交的版本，檢視最新版本。
此腳本不應該直接安裝，它是一個供其他腳本使用的函式庫。欲使用本函式庫，請在腳本 metadata 寫上： // @require https://update.cn-greasyfork.org/scripts/29174/189853/XPath.js
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換行
// ==UserScript==
// @name           XPath
// @namespace      http://gm.wesley.eti.br/includes
// @description    xpath Function
// @author         w35l3y
// @email          [email protected]
// @copyright      2009+, w35l3y (http://gm.wesley.eti.br)
// @license        GNU GPL
// @homepage       http://gm.wesley.eti.br
// @version        1.0.0.5
// @language       en
// @include        nowhere
// ==/UserScript==

/**************************************************************************

	Author 's NOTE

    Original http://lowreal.net/blog/2007/11/17/1

***************************************************************************

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

**************************************************************************/

XPath = Xpath = xpath = function()
{
    var a = Array.prototype.slice.call(arguments),	// args
        e = a[0],	// expression
        c = a[1],	// context
        t = a[2];	// type

    if (typeof c == "function")
    {
        t = c;
        c = null;
    }
    if (!c)
        c = document.documentElement||document;
    var d = c.ownerDocument || c;
    e = d.createExpression(e, function(p)
                           {
        var o = d.createNSResolver(c).lookupNamespaceURI(p);

        if (o)
            return o;
        else switch (c.contentType)
        {
            case "text/xhtml":
            case "application/xhtml+xml":
                return "http://www.w3.org/1999/xhtml";
            default:
                return "";
        }
    });

    switch (t)
    {
        case String:
            return e.evaluate(c, XPathResult.STRING_TYPE, null).stringValue;
        case Number:
            return e.evaluate(c, XPathResult.NUMBER_TYPE, null).numberValue;
        case Boolean:
            return e.evaluate(c, XPathResult.BOOLEAN_TYPE, null).booleanValue;
        case Array:
            var r = e.evaluate(c, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null),
                o = [];

            for ( var ai = 0 , at = r.snapshotLength ; ai < at ; ++ai )
                o.push(r.snapshotItem(ai));

            return o;
        case undefined:
            r = e.evaluate(c, XPathResult.ANY_TYPE, null);
            switch (r.resultType)
            {
                case XPathResult.STRING_TYPE:
                    return r.stringValue;
                case XPathResult.NUMBER_TYPE:
                    return r.numberValue;
                case XPathResult.BOOLEAN_TYPE:
                    return r.booleanValue;
                case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
                    var o = [], i;
                    while (i == r.iterateNext())
                        o.push(i);

                    return o;
            }
            return null;
        default:
            throw(TypeError("xpath: specified type is not valid type."));
    }
};