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.txtAddress.value == "") {
    alert( "Xin vui long nhap [Dia chi] !" );
    form.txtAddress.focus();
    return false ;
  }
  if (form.txtPhone.value == "") {
    alert( "Xin vui long nhap [Dien thoai] !" );
    form.txtPhone.focus();
    return false ;
  }

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

  if (form.txtContent.value == "") {
    alert( "Xin vui long nhap [Noi dung] !" );
    form.txtContent.focus();
    return false ;
  }

  return true ;
}