Sales Order Alert Button

I am trying to retrieve the text in Memo field for display.
Something is not right and it is only giving me the result of
" There is no memo"

I am running this as a button on Sales Order... Help..



function specialMessage(){
/*
  * Client script to alert of any special message
  */
var memo = nlapiGetFieldValue('memo');
var memo_text = nlapiGetFieldText('memo');
if (memo_text !== null) {

  alert('Please note the memo on this customer' + memo);
  alert('The text for terms is ' + memo_text);
}
else
  alert('There is no memo');
// end function with return back to main NetSuite function
return true;
}