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selectSingleNode method (XMLDocument)

Browser support:

Returns the first node that matches the specified XPath expression on the current node.

In Firefox, Google Chrome and Safari (and optionally in Opera), use the evaluate method instead.

Syntax:

object.selectSingleNode (xpathExpression);

You can find the related objects in the Supported by objects section below.

Parameters:

xpathExpression

Required. String that specifies the XPath expression to evaluate. For more information, please visit the Location Paths (W3C) page.

Return value:

Returns the first matching node or null.

Example HTML code 1:

This example illustrates the use of the selectSingleNode method:

Code

ajax.js

news.xml

<head>
    <script type="text/javascript" src="ajax.js"></script>
    
    <script type="text/javascript">
        var httpRequest = null;
        
        function SendRequest () {
            if (!httpRequest) {
                httpRequest = CreateHTTPRequestObject ();   // defined in ajax.js
            }
            if (httpRequest) {          
                    // The requested file must be in the same domain that the page is served from.
                var url = "news.xml";
                httpRequest.open ("GET", url, true);    // async
                httpRequest.onreadystatechange = OnStateChange;
                httpRequest.send (null);
            }
        }

        function OnStateChange () {
            if (httpRequest.readyState == 0 || httpRequest.readyState == 4) {
                if (IsRequestSuccessful (httpRequest)) {    // defined in ajax.js
                    Test_SelectSingleNode ();
                }
                else {
                    alert ("Operation failed.");
                }
            }
        }

        function Test_SelectSingleNode () {
            var xmlDoc = ParseHTTPResponse (httpRequest);   // defined in ajax.js
            if (!xmlDoc)
                return;

            if ('selectSingleNode' in xmlDoc) {
                var xmlNode = xmlDoc.selectSingleNode ("news/channel/item/title");
                if ('textContent' in xmlNode)
                    alert (xmlNode.textContent);
                else
                    alert (xmlNode.text);
            }
            else {
                alert ("Your browser doesn't support the selectSingleNode method!");
            }
        }
    </script>
</head>
<body>
    <button onclick="SendRequest ()">Test selectSingleNode method</button>
</body>


function CreateHTTPRequestObject () {
        // although IE supports the XMLHttpRequest object, but it does not work on local files.
    var forceActiveX = (window.ActiveXObject && location.protocol === "file:");
    if (window.XMLHttpRequest && !forceActiveX) {
        return new XMLHttpRequest();
    }
    else {
        try {
            return new ActiveXObject("Microsoft.XMLHTTP");
        } catch(e) {}
    }
    alert ("Your browser doesn't support XML handling!");
    return null;
}

function CreateMSXMLDocumentObject () {
    if (typeof (ActiveXObject) != "undefined") {
        var progIDs = [
                        "Msxml2.DOMDocument.6.0", 
                        "Msxml2.DOMDocument.5.0", 
                        "Msxml2.DOMDocument.4.0", 
                        "Msxml2.DOMDocument.3.0", 
                        "MSXML2.DOMDocument", 
                        "MSXML.DOMDocument"
                      ];
        for (var i = 0; i < progIDs.length; i++) {
            try { 
                return new ActiveXObject(progIDs[i]); 
            } catch(e) {};
        }
    }
    return null;
}

function CreateXMLDocumentObject (rootName) {
    if (!rootName) {
        rootName = "";
    }
    var xmlDoc = CreateMSXMLDocumentObject ();
    if (xmlDoc) {
        if (rootName) {
            var rootNode = xmlDoc.createElement (rootName);
            xmlDoc.appendChild (rootNode);
        }
    }
    else {
        if (document.implementation.createDocument) {
            xmlDoc = document.implementation.createDocument ("", rootName, null);
        }
    }
    
    return xmlDoc;
}

function ParseHTTPResponse (httpRequest) {
    var xmlDoc = httpRequest.responseXML;

            // if responseXML is not valid, try to create the XML document from the responseText property
    if (!xmlDoc || !xmlDoc.documentElement) {
        if (window.DOMParser) {
            var parser = new DOMParser();
            try {
                xmlDoc = parser.parseFromString (httpRequest.responseText, "text/xml");
            } catch (e) {
                alert ("XML parsing error");
                return null;
            };
        }
        else {
            xmlDoc = CreateMSXMLDocumentObject ();
            if (!xmlDoc) {
                return null;
            }
            xmlDoc.loadXML (httpRequest.responseText);

        }
    }

            // if there was an error while parsing the XML document
    var errorMsg = null;
    if (xmlDoc.parseError && xmlDoc.parseError.errorCode != 0) {
        errorMsg = "XML Parsing Error: " + xmlDoc.parseError.reason
                  + " at line " + xmlDoc.parseError.line
                  + " at position " + xmlDoc.parseError.linepos;
    }
    else {
        if (xmlDoc.documentElement) {
            if (xmlDoc.documentElement.nodeName == "parsererror") {
                errorMsg = xmlDoc.documentElement.childNodes[0].nodeValue;
            }
        }
    }
    if (errorMsg) {
        alert (errorMsg);
        return null;
    }

        // ok, the XML document is valid
    return xmlDoc;
}

    // returns whether the HTTP request was successful
function IsRequestSuccessful (httpRequest) {
        // IE: sometimes 1223 instead of 204
    var success = (httpRequest.status == 0 || 
        (httpRequest.status >= 200 && httpRequest.status < 300) || 
        httpRequest.status == 304 || httpRequest.status == 1223);
    
    return success;
}

<?xml version="1.0" encoding="utf-8"?>
<news>
    <channel>
        <item>
            <title>Paula Abdul leaves American Idol</title>
            <description>Paula Abdul has officially confirmed that she won’t be returning to American Idol this season. "With sadness in my heart, I’ve decided not to return to Idol," she wrote on her Twitter page.</description>
            <pubDate>Wed, August 5, 2009 19:52:31 +0200</pubDate>
            <link>http://www.tribute.ca/news/index.php/its-official-paula-abdul-leaves-american-idol/2009/08/05/</link>
        </item>

        <item>
            <title>Criminal Minds star Moore hit by car</title>
            <description>Shemar Moore, 39, who plays FBI Agent Derek Morgan in the CBS drama Criminal Minds, was hit by a car while bicycling in Los Angeles last Saturday.</description>
            <pubDate>Thu, August 4, 2009 13:28:12 +0200</pubDate>
            <link>http://www.tribute.ca/news/index.php/criminal-minds-star-moore-hit-by-car/2009/08/04/</link>
        </item>

        <item>
            <title>Madonna writes love song for ex-husband</title>
            <description>Madonna has sparked speculation that she wants to get back with her ex-husband, Guy Ritchie, after writing a love song for him in which she calls him her "eternal love".</description>
            <pubDate>Fri, July 31, 2009 04:01:50 +0200</pubDate>
            <link>http://www.tribute.ca/news/index.php/madonna-writes-love-song-for-ex-husband/2009/07/31/</link>
        </item>
    </channel>
</news>