var invalidChars = new String("<>");

function ValidateString(fieldName,AlertMsg)
{
   return ValidateStringEx(fieldName,AlertMsg,false);
}

function ValidateStringEx(fieldName,AlertMsg,checkSpecialChars)
{
   var field = MM_findObj(fieldName);
   var ReturnValue = true;

   if (field == null) return true;

   if ((field.type != "text") && (field.type != "textarea") && (field.type != "password"))
   {
      window.alert(fieldName + ": Not a text field");
      ReturnValue = false;
   }
   else
   {
      if (field.value == '')
      {
         ReturnValue = false;
      }
      else if (checkSpecialChars == true)
      {
         for (var i = 0; i < invalidChars.length; i++)
         {
            if (field.value.indexOf(invalidChars.substring(i, i+1)) != -1)
            {
               ReturnValue = false;
               break;
            }
         }
      }

      if (ReturnValue == false)
      {
         window.alert(AlertMsg);
         field.focus();
      }
   }
   return ReturnValue;
}