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getResponseHeader method (XMLHttpRequest)

Browser support:

Returns the value of the specified response header.

The response headers contain information about the server and the retrieved content ('Content-Length', 'Content-Type', ...). To get all response headers together, use the getAllResponseHeaders method.

Syntax:

object.getResponseHeader (name);

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

Parameters:

name

Required. String that specifies the name of the response header to retrieve. The following list contains some of the commonly used names. If you need a more complete list, please visit the HTTP response headers (Wikipedia) page.

Content-Length

The size of the response body, in bytes.

Content-Type

The content type of the response body.

Date

The current server time when the response was sent.

Last-Modified

The date and time when the resource was last modified.

Server

The type and version of the web server.

Return value:

String. The value of the specified response header.

Example HTML code 1:

This example illustrates the use of the getResponseHeader 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_ResponseHeaders ();
                }
                else {
                    alert ("Operation failed.");
                }
            }
        }

        function Test_ResponseHeaders () {
            var contType = httpRequest.getResponseHeader ("Content-Type");
            var contLength = httpRequest.getResponseHeader ("Content-Length");
            var lastMod = httpRequest.getResponseHeader ("Last-Modified");
            alert ("Content-Type: " + contType + "\n" + 
                   "Content-Length: " + contLength + "\n" +
                   "Last-Modified: " + lastMod);
        }

    </script>
</head>
<body>
    <button onclick="SendRequest ()">Test response headers</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>