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isDefaultNamespace method

Browser support:

9

Returns whether the specified namespace URI is the default namespace in the scope of the current node.

Note: The isDefaultNamespace method of HTML elements and attributes is only supported in Firefox, Safari, Google Chrome and Internet Explorer from version 9. The default namespace for HTML elements and attributes is an empty string in Firefox, and "http://www.w3.org/1999/xhtml" in Google Chrome, Safari and Internet Explorer. In Opera, the isDefaultNamespace method always returns false on HTML elements and attributes.

Note: The isDefaultNamespace method is not supported in Internet Explorer in XML documents.

To get the namespace prefix that is associated with a namespace URI, use the lookupPrefix method. To get the namespace URI that is associated with a namespace prefix, use the lookupNamespaceURI method.

Syntax:

object.isDefaultNamespace (namespaceURI);

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

Parameters:

namespaceURI

Required. String that specifies the namespace URI to test.

Return value:

Boolean. One of the following values:

false	The specified namespace URI is not the default namespace.
true	The specified namespace URI is the default namespace.

Example HTML code 1:

This example illustrates the use of the isDefaultNamespace method:

Code

ajax.js

ns.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 = "ns.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
                    TestDefaultNamespace ();
                }
                else {
                    alert ("Operation failed.");
                }
            }
        }

        function TestDefaultNamespace () {
            var xmlDoc = ParseHTTPResponse (httpRequest);   // defined in ajax.js
            if (!xmlDoc)
                return;
                
            var firstItem = xmlDoc.getElementsByTagName ("item")[0];
            if (firstItem.isDefaultNamespace) {
                var isDef = firstItem.isDefaultNamespace ("http://help.dottoro.com/defaultNS");
                alert ("Is the 'http://help.dottoro.com/defaultNS namespace the default?\n" + isDef);
                var isDef = firstItem.isDefaultNamespace ("http://help.dottoro.com/NS");
                alert ("Is the 'http://help.dottoro.com/NS' namespace the default?\n" + isDef);
            }
            else {
                alert ("Your browser doesn't support the isDefaultNamespace method.");
            }
        }
    </script>
</head>
<body>
    <button onclick="SendRequest ()">Test the default namespace</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"?>
<ns xmlns="http://help.dottoro.com/defaultNS" xmlns:dotto="http://help.dottoro.com/NS">
    <item dotto:color="red">
        <dotto:title>Namespace example</dotto:title>
        <dotto:description>Describes how to use namespaces with tags and attributes.</dotto:description>
        <dotto:pubDate>Wed, 17 Aug 2009 13:58:41 +0200</dotto:pubDate>
        <dotto:link>http://help.dottoro.com</dotto:link>
    </item>
    <order>
        <dotto:param name="sortBy" value="title" />
        <dotto:param name="sortDir" value="ascending" />
    </order>
</ns>