// Common variables
var READYSTATE_UNINITIALIZED = 0;
var READYSTATE_LOADING = 1;
var READYSTATE_LOADED = 2;
var READYSTATE_INTERACTIVE = 3;
var READYSTATE_COMPLETE = 4;

// Common values for HTTP status codes
var HTTPSTATUS_OK = 200;
var HTTPSTATUS_NOTFOUND = 404;
var HTTPSTATUS_SERVERERROR = 500;

// create http request object
function CreateXmlHttpRequestObject() {
    
    if (window.XMLHttpRequest) {
        xmlHttpObj = new XMLHttpRequest();
    }
    else
    {
        try
        {
            xmlHttpObj = new ActiveXObject("Microsoft.XMLHTTP");
        }
        catch(e)
        {
            xmlHttpObj = new ActiveXObject("Msxml2.XMLHTTP");
        }
     }
     
     return xmlHttpObj;
}

// is the value numeric?
function IsNumeric(sText)
{
   var ValidChars = "0123456789.";
   var IsNumber=true;
   var Char;
 
   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
   return IsNumber;
   
 }