//  check for valid numeric strings	
function IsNumeric(strString)
{
   //strString=strString.replace(",", ".")
   var strValidChars = "0123456789.";
   var strChar;
   var blnResult = true;

   if (strString.length == 0) return false;

   //  test strString consists of valid characters listed above
   for (i = 0; i < strString.length && blnResult == true; i++){
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1){
         blnResult = false;
      }
   }
   return blnResult;
}