onsubmit return non funziona

[br1]

<script language="JavaScript" type="text/JavaScript">

var good = true;

function checkEmailAddress(field) {

  var goodEmail = field.value.match(/\b(^(\S+@).+((\.com)|(\.net)|(\.edu)|(\.mil)|(\.gov)|(\.org)|(\..{2,2}))$)\b/gi);

  if (!goodEmail){
    alert('Devi inserire un indirizzo email valido!')
    field.focus()
    field.select()
    good = false
  }
}

function sendOff(){
  nomecheck = document.Form.nome.value    
  if (nomecheck.length <1) {
    alert('Devi inserire il tuo nome!')
    good = false
  }         
  checkEmailAddress(document.Form.mail)
  if ((document.Form.mail.value !=
    document.Form.remail.value)&&(good)){
    alert('Gli indirizzi email non coincidono!')
    good = false
  }
  if ((document.Form.mail.value == document.Form.remail.value)&&(good)){
    alert("La mail verra' inviata tra pochi istanti!")
  }     
  return good;
}
</script>

ciao