如何使用Firebug xpath.js脚本？

Question

I am trying to use this script over here: https://github.com/firebug/firebug/blob/master/extension/content/firebug/lib/xpath.js

see here:

/* See license.txt for terms of usage */

define([
    "firebug/lib/string"
],
function(Str) {

"use strict";

// ********************************************************************************************* //
// Constants

var Xpath = {};

// ********************************************************************************************* //
// XPATH

/**
 * Gets an XPath for an element which describes its hierarchical location.
 */
Xpath.getElementXPath = function(element)
{
    if (element && element.id)
        return '//*[@id="' + element.id + '"]';
    else
        return Xpath.getElementTreeXPath(element);
};

Xpath.getElementTreeXPath = function(element)
{
    var paths = [];

    // Use nodeName (instead of localName) so namespace prefix is included (if any).
    for (; element && element.nodeType == Node.ELEMENT_NODE; element = element.parentNode)
    {
        var index = 0;
        var hasFollowingSiblings = false;
        for (var sibling = element.previousSibling; sibling; sibling = sibling.previousSibling)
        {
            // Ignore document type declaration.
            if (sibling.nodeType == Node.DOCUMENT_TYPE_NODE)
                continue;

            if (sibling.nodeName == element.nodeName)
                ++index;
        }

        for (var sibling = element.nextSibling; sibling && !hasFollowingSiblings;
            sibling = sibling.nextSibling)
        {
            if (sibling.nodeName == element.nodeName)
                hasFollowingSiblings = true;
        }

        var tagName = (element.prefix ? element.prefix + ":" : "") + element.localName;
        var pathIndex = (index || hasFollowingSiblings ? "[" + (index + 1) + "]" : "");
        paths.splice(0, 0, tagName + pathIndex);
    }

    return paths.length ? "/" + paths.join("/") : null;
};

Xpath.cssToXPath = function(rule)
{
    var regElement = /^([#.]?)([a-z0-9\\*_-]*)((\|)([a-z0-9\\*_-]*))?/i;
    var regAttr1 = /^\[([^\]]*)\]/i;
    var regAttr2 = /^\[\s*([^~=\s]+)\s*(~?=)\s*"([^"]+)"\s*\]/i;
    var regPseudo = /^:([a-z_-])+/i;
    var regCombinator = /^(\s*[>+\s])?/i;
    var regComma = /^\s*,/i;

    var index = 1;
    var parts = ["//", "*"];
    var lastRule = null;

    while (rule.length && rule != lastRule)
    {
        lastRule = rule;

        // Trim leading whitespace
        rule = Str.trim(rule);
        if (!rule.length)
            break;

        // Match the element identifier
        var m = regElement.exec(rule);
        if (m)
        {
            if (!m[1])
            {
                // XXXjoe Namespace ignored for now
                if (m[5])
                    parts[index] = m[5];
                else
                    parts[index] = m[2];
            }
            else if (m[1] == '#')
                parts.push("[@id='" + m[2] + "']");
            else if (m[1] == '.')
                parts.push("[contains(concat(' ',normalize-space(@class),' '), ' " + m[2] + " ')]");

            rule = rule.substr(m[0].length);
        }

        // Match attribute selectors
        m = regAttr2.exec(rule);
        if (m)
        {
            if (m[2] == "~=")
                parts.push("[contains(@" + m[1] + ", '" + m[3] + "')]");
            else
                parts.push("[@" + m[1] + "='" + m[3] + "']");

            rule = rule.substr(m[0].length);
        }
        else
        {
            m = regAttr1.exec(rule);
            if (m)
            {
                parts.push("[@" + m[1] + "]");
                rule = rule.substr(m[0].length);
            }
        }

        // Skip over pseudo-classes and pseudo-elements, which are of no use to us
        m = regPseudo.exec(rule);
        while (m)
        {
            rule = rule.substr(m[0].length);
            m = regPseudo.exec(rule);
        }

        // Match combinators
        m = regCombinator.exec(rule);
        if (m && m[0].length)
        {
            if (m[0].indexOf(">") != -1)
                parts.push("/");
            else if (m[0].indexOf("+") != -1)
                parts.push("/following-sibling::");
            else
                parts.push("//");

            index = parts.length;
            parts.push("*");
            rule = rule.substr(m[0].length);
        }

        m = regComma.exec(rule);
        if (m)
        {
            parts.push(" | ", "//", "*");
            index = parts.length-1;
            rule = rule.substr(m[0].length);
        }
    }

    var xpath = parts.join("");
    return xpath;
};

Xpath.getElementsBySelector = function(doc, css)
{
    var xpath = Xpath.cssToXPath(css);
    return Xpath.getElementsByXPath(doc, xpath);
};

Xpath.getElementsByXPath = function(doc, xpath)
{
    try
    {
        return Xpath.evaluateXPath(doc, xpath);
    }
    catch(ex)
    {
        return [];
    }
};

/**
 * Evaluates an XPath expression.
 *
 * @param {Document} doc
 * @param {String} xpath The XPath expression.
 * @param {Node} contextNode The context node.
 * @param {int} resultType
 *
 * @returns {*} The result of the XPath expression, depending on resultType :<br> <ul>
 *          <li>if it is XPathResult.NUMBER_TYPE, then it returns a Number</li>
 *          <li>if it is XPathResult.STRING_TYPE, then it returns a String</li>
 *          <li>if it is XPathResult.BOOLEAN_TYPE, then it returns a boolean</li>
 *          <li>if it is XPathResult.UNORDERED_NODE_ITERATOR_TYPE
 *              or XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, then it returns an array of nodes</li>
 *          <li>if it is XPathResult.ORDERED_NODE_SNAPSHOT_TYPE
 *              or XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, then it returns an array of nodes</li>
 *          <li>if it is XPathResult.ANY_UNORDERED_NODE_TYPE
 *              or XPathResult.FIRST_ORDERED_NODE_TYPE, then it returns a single node</li>
 *          </ul>
 */
Xpath.evaluateXPath = function(doc, xpath, contextNode, resultType)
{
    if (contextNode === undefined)
        contextNode = doc;

    if (resultType === undefined)
        resultType = XPathResult.ANY_TYPE;

    var result = doc.evaluate(xpath, contextNode, null, resultType, null);

    switch (result.resultType)
    {
        case XPathResult.NUMBER_TYPE:
            return result.numberValue;

        case XPathResult.STRING_TYPE:
            return result.stringValue;

        case XPathResult.BOOLEAN_TYPE:
            return result.booleanValue;

        case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
        case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
            var nodes = [];
            for (var item = result.iterateNext(); item; item = result.iterateNext())
                nodes.push(item);
            return nodes;

        case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE:
        case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
            var nodes = [];
            for (var i = 0; i < result.snapshotLength; ++i)
                nodes.push(result.snapshotItem(i));
            return nodes;

        case XPathResult.ANY_UNORDERED_NODE_TYPE:
        case XPathResult.FIRST_ORDERED_NODE_TYPE:
            return result.singleNodeValue;
    }
};

Xpath.getRuleMatchingElements = function(rule, doc)
{
    var css = rule.selectorText;
    var xpath = Xpath.cssToXPath(css);
    return Xpath.getElementsByXPath(doc, xpath);
};

// ********************************************************************************************* //
// Registration

return Xpath;

// ********************************************************************************************* //
});

As I only have some basic knowledge of Javascript, I want to ask, how to call the functions that are defined inside that script from a different js file, eg the function getElementTreeXPath and what the parameter element has to look like.

Can someone help?

Answer 1

Here is an example on how to use the code presented in your snippet, as define is not part of client-side Javascript I have only used the rest of the code and put it into a script element, of course you could as well put it into an external script file. As for the element argument, that is supposed to be a DOM element node found in an HTML document:

 document.addEventListener( 'click', function(evt) { document.body.insertAdjacentHTML('beforeEnd', '<p>Clicked ' + evt.target + ' with path ' + Xpath.getElementXPath(evt.target) + '.<\\/p>'); }, false ); 

 <script> //extracted from https://github.com/firebug/firebug/blob/master/extension/content/firebug/lib/xpath.js //see licence https://github.com/firebug/firebug/blob/master/extension/license.txt "use strict"; // ********************************************************************************************* // // Constants var Xpath = {}; // ********************************************************************************************* // // XPATH /** * Gets an XPath for an element which describes its hierarchical location. */ Xpath.getElementXPath = function(element) { if (element && element.id) return '//*[@id="' + element.id + '"]'; else return Xpath.getElementTreeXPath(element); }; Xpath.getElementTreeXPath = function(element) { var paths = []; // Use nodeName (instead of localName) so namespace prefix is included (if any). for (; element && element.nodeType == Node.ELEMENT_NODE; element = element.parentNode) { var index = 0; var hasFollowingSiblings = false; for (var sibling = element.previousSibling; sibling; sibling = sibling.previousSibling) { // Ignore document type declaration. if (sibling.nodeType == Node.DOCUMENT_TYPE_NODE) continue; if (sibling.nodeName == element.nodeName) ++index; } for (var sibling = element.nextSibling; sibling && !hasFollowingSiblings; sibling = sibling.nextSibling) { if (sibling.nodeName == element.nodeName) hasFollowingSiblings = true; } var tagName = (element.prefix ? element.prefix + ":" : "") + element.localName; var pathIndex = (index || hasFollowingSiblings ? "[" + (index + 1) + "]" : ""); paths.splice(0, 0, tagName + pathIndex); } return paths.length ? "/" + paths.join("/") : null; }; Xpath.cssToXPath = function(rule) { var regElement = /^([#.]?)([a-z0-9\\\\*_-]*)((\\|)([a-z0-9\\\\*_-]*))?/i; var regAttr1 = /^\\[([^\\]]*)\\]/i; var regAttr2 = /^\\[\\s*([^~=\\s]+)\\s*(~?=)\\s*"([^"]+)"\\s*\\]/i; var regPseudo = /^:([a-z_-])+/i; var regCombinator = /^(\\s*[>+\\s])?/i; var regComma = /^\\s*,/i; var index = 1; var parts = ["//", "*"]; var lastRule = null; while (rule.length && rule != lastRule) { lastRule = rule; // Trim leading whitespace rule = Str.trim(rule); if (!rule.length) break; // Match the element identifier var m = regElement.exec(rule); if (m) { if (!m[1]) { // XXXjoe Namespace ignored for now if (m[5]) parts[index] = m[5]; else parts[index] = m[2]; } else if (m[1] == '#') parts.push("[@id='" + m[2] + "']"); else if (m[1] == '.') parts.push("[contains(concat(' ',normalize-space(@class),' '), ' " + m[2] + " ')]"); rule = rule.substr(m[0].length); } // Match attribute selectors m = regAttr2.exec(rule); if (m) { if (m[2] == "~=") parts.push("[contains(@" + m[1] + ", '" + m[3] + "')]"); else parts.push("[@" + m[1] + "='" + m[3] + "']"); rule = rule.substr(m[0].length); } else { m = regAttr1.exec(rule); if (m) { parts.push("[@" + m[1] + "]"); rule = rule.substr(m[0].length); } } // Skip over pseudo-classes and pseudo-elements, which are of no use to us m = regPseudo.exec(rule); while (m) { rule = rule.substr(m[0].length); m = regPseudo.exec(rule); } // Match combinators m = regCombinator.exec(rule); if (m && m[0].length) { if (m[0].indexOf(">") != -1) parts.push("/"); else if (m[0].indexOf("+") != -1) parts.push("/following-sibling::"); else parts.push("//"); index = parts.length; parts.push("*"); rule = rule.substr(m[0].length); } m = regComma.exec(rule); if (m) { parts.push(" | ", "//", "*"); index = parts.length-1; rule = rule.substr(m[0].length); } } var xpath = parts.join(""); return xpath; }; Xpath.getElementsBySelector = function(doc, css) { var xpath = Xpath.cssToXPath(css); return Xpath.getElementsByXPath(doc, xpath); }; Xpath.getElementsByXPath = function(doc, xpath) { try { return Xpath.evaluateXPath(doc, xpath); } catch(ex) { return []; } }; /** * Evaluates an XPath expression. * * @param {Document} doc * @param {String} xpath The XPath expression. * @param {Node} contextNode The context node. * @param {int} resultType * * @returns {*} The result of the XPath expression, depending on resultType :<br> <ul> * <li>if it is XPathResult.NUMBER_TYPE, then it returns a Number</li> * <li>if it is XPathResult.STRING_TYPE, then it returns a String</li> * <li>if it is XPathResult.BOOLEAN_TYPE, then it returns a boolean</li> * <li>if it is XPathResult.UNORDERED_NODE_ITERATOR_TYPE * or XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, then it returns an array of nodes</li> * <li>if it is XPathResult.ORDERED_NODE_SNAPSHOT_TYPE * or XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, then it returns an array of nodes</li> * <li>if it is XPathResult.ANY_UNORDERED_NODE_TYPE * or XPathResult.FIRST_ORDERED_NODE_TYPE, then it returns a single node</li> * </ul> */ Xpath.evaluateXPath = function(doc, xpath, contextNode, resultType) { if (contextNode === undefined) contextNode = doc; if (resultType === undefined) resultType = XPathResult.ANY_TYPE; var result = doc.evaluate(xpath, contextNode, null, resultType, null); switch (result.resultType) { case XPathResult.NUMBER_TYPE: return result.numberValue; case XPathResult.STRING_TYPE: return result.stringValue; case XPathResult.BOOLEAN_TYPE: return result.booleanValue; case XPathResult.UNORDERED_NODE_ITERATOR_TYPE: case XPathResult.ORDERED_NODE_ITERATOR_TYPE: var nodes = []; for (var item = result.iterateNext(); item; item = result.iterateNext()) nodes.push(item); return nodes; case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE: case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE: var nodes = []; for (var i = 0; i < result.snapshotLength; ++i) nodes.push(result.snapshotItem(i)); return nodes; case XPathResult.ANY_UNORDERED_NODE_TYPE: case XPathResult.FIRST_ORDERED_NODE_TYPE: return result.singleNodeValue; } }; Xpath.getRuleMatchingElements = function(rule, doc) { var css = rule.selectorText; var xpath = Xpath.cssToXPath(css); return Xpath.getElementsByXPath(doc, xpath); }; </script> <div> <h1>Example</h1> <p id=p1>This is a paragraph with some <b>bold</b> text.</p> <p>Click some content in the page to see XPath of clicked element.</p> </div>