function ValidateForm(form)
{
   if (IsEmpty(form.DFES)) 
   { 
      alert('Please enter an account number');
      return false; 
   } 

   if ((form.DFES.value.length) > 5) 
   { 
      alert('Please check the account number it seems too long');
      return false; 
   } 

}

function IsEmpty(aTextField) {
   if ((aTextField.value.length==0) || (aTextField.value==null)) 
     {
       return true;
     }
   else {return false;}
}

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;
}