function callService(sPostData,ResponseFunction)
{ 
    var xhr; 
    try {xhr = new ActiveXObject('Msxml2.XMLHTTP');   }
    catch (e) 
    {
        try {xhr = new ActiveXObject('Microsoft.XMLHTTP');}
        catch (e2) 
        {
          try {  xhr = new XMLHttpRequest(); }
          catch (e3) {  xhr = false;   }
        }
     }
  
    xhr.onreadystatechange  = function()
    { 
         if(xhr.readyState  == 4)
         {
              if(xhr.status  == 200)               
                  eval(ResponseFunction); 
         }
    }; 
    
    xhr.open("POST", "WebServices/Services.aspx/", true); 
    xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");                  
    xhr.send(sPostData); 
}