On click of a button my page(Firstpage.aspx) calls the server side C# code and the Dataset writes the data from Database to a xml file

ds.WriteXml(Server.MapPath("dsXML.xml"));

I want to pass this dsXML.xml file to my Client system so that I can manipulate the data at my Client Side Javascript code.

Hi,
You need not do it at all. You can read your XML in javascrip by simple.
                   var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
                   loadXML('XMLFiles/dsXML.xml');
                   function loadXML(xmlFile)
            {
            xmlDoc.async="false";
            xmlDoc.onreadystatechange=verify;
            xmlDoc.load(xmlFile);
            xmlObj=xmlDoc.documentElement;
            }
Now your XML file is in xmlObj. You can work with it.

Dharmendra