XML Parsing and other XML Utilities - Cross Browser

Hello,

Are you searching for an alternative to new ActiveXObject("Microsoft.XMLDOM") which will work in all popular browsers? Then here it is a solution.

This Javascript library will give you the possibility to do almost everything what you could do with ActiveXObject("Microsoft.XMLDOM") but in different browsers.



Note: jQuery Core and jQuery UI is used in this Javascript library.

Code:

MSXML = [
 "Msxml2.DOMDocument.6.0",
 "Msxml2.DOMDocument.5.0",
 "Msxml2.DOMDocument.4.0",
 "Msxml2.DOMDocument.3.0",
 "MSXML2.DOMDocument",
 "Microsoft.XMLDOM"
];

function createDocument() {
    var doc;
    if (document.implementation && document.implementation.createDocument) {
        doc = document.implementation.createDocument("", "", null);
    } else if (window.ActiveXObject) {
        for (var i = 0; i < MSXML.length; i++) {
            try {
                doc = new ActiveXObject(MSXML[i]);
            } catch (e) { }
        }
        if (!doc) {
            alert("Cannot create XMLDocument object");
            return false;
        }
    }
    return doc;
}

function parseXML(str) {
    if (str == null) return null;
    if ($.trim(str) == "") return createDocument();
  
    var dom = str;
    if ($.browser.msie) {
        dom = new ActiveXObject("Microsoft.XMLDOM");
        dom.async = "false";
        dom.loadXML(str);
    }
    else if (typeof (DOMParser) != "undefined") {
        var parser = new DOMParser();
        try {

            dom = parser.parseFromString(str, "text/xml");
        } catch (e) { };

    }

    var errorMsg = null;
    if (dom.parseError && dom.parseError.errorCode != 0) {
        errorMsg = "XML Parsing Error: " + dom.parseError.reason
                          + " at line " + dom.parseError.line
                          + " at position " + dom.parseError.linepos;
    }
    else {
        if (dom.documentElement) {
            if (dom.documentElement.nodeName == "parsererror") {
                errorMsg = xmlDoc.documentElement.childNodes[0].nodeValue;
            }
        }
        else {
            errorMsg = "XML Parsing Error!";
        }
    }

    if (errorMsg) {
        //alert(errorMsg);
        return false;
    }
  
    return dom;
}

function parseXMLUrl(xmlURL) {
    var doc = createDocument();

    if (doc && typeof doc.load != 'undefined') {
        doc.async = false;
        doc.load(xmlURL);
        return doc;
    } else {
        var request = new XMLHttpRequest();
        request.open("GET", xmlURL, false);
        request.send("");
        return request.responseXML;
    }
}

function getXMLAsString(xmlDoc) {
    if (xmlDoc == null) return null;
    return ($.browser.msie) ? xmlDoc.xml : (new XMLSerializer()).serializeToString(xmlDoc);
}

function selectNodes(xmlDoc, xPath) {
    if (xmlDoc == null) return null;
    var condition = xPath;
    condition = condition.substring(0, 1) == "/" ? condition.substring(1, condition.length) : condition;
    condition = condition.replace(new RegExp("/","g"), ">").replace(new RegExp("@","g"), "");

    return $(xmlDoc).find(condition);
}

function selectSingleNode(xmlDoc, xPath) {
    if (xmlDoc == null) return null;
    var nodes = selectNodes(xmlDoc, xPath);
    if (nodes.length > 0) {
        return nodes[0];
    }
    return null;
}

This library provides a set of functions which you will use instead of standard ones.

For example

1) When you want to create an instance of XMLDOM then use CreateDocument() function. i.e.

              var xmlObj = CreateDocument();

              // Instead of:

              var xmlObj = new ActiveXObject("Microsoft.XMLDOM") ;

2) When you want to load a xml into an xmlObject then instead of a set of operations you will have to write only one line of code. i.e.

              var xmlObj = parseXML('');

              // Instead of:

              var xmlObj = new ActiveXObject("Microsoft.XMLDOM");

              xmlObj .async = "false";

              xmlObj .loadXML('');

3) When you want to load a xml from an URL then instead of a set of operations you will have to write only one line of code(again :) ). i.e.

              var xmlObj = parseXMLUrl('XMLParsing.com/CrossBrowser');

              // Instead of:

              var xmlObj = new ActiveXObject("Microsoft.XMLDOM");

              doc.async = false;

              doc.load(xmlURL);

4) Use getXMLAsString(xmlObj) instead of xmlObj.xml

5) To select some nodes which corresponds to a xPath condition use selectNodes(xmlObj, xPath), as like you were using it with xmlObj.selectNodes(xPath);

6) And the last one: selectSingleNode, its alternative is selectSingleNode(xmlObj, xPath).

And again, if you have any suggestion for improvement please tell me. Let me know your impressions about this post.

UPDATE on 20 Feb 2011:
I have noted that the team from jQuery has achieved the same parseXML as me. :) in jQuery core 1.5.