function checkform ( form )
{

  if (form.txtFullName.value == "") {
    alert( "Xin vui long nhap [Ten cong ty] !" );
    form.txtFullName.focus();
    return false ;
  }

  if (form.txtPerson.value == "") {
    alert( "Xin vui long nhap [Ten nguoi lien he] !" );
    form.txtPerson.focus();
    return false ;
  }
    if (form.txtEmail.value == "") {
    alert( "Xin vui long nhap [Dia chi Email] !" );
    form.txtEmail.focus();
    return false ;
  }
  return true ;
}