ใครเคยทำ FPDF เซ้ต footer ในหน้าสุดท้าย {nb} บ้างครับ

<?php
require('fpdf.php');

class PDF extends FPDF
{
//Page header
function Header()
{
//Logo
//$this->Image('logo_pb.png',10,8,33);
//Arial bold 15
$this->SetFont('Arial','B',15);
//Move to the right
$this->Cell(80);
//Title
$this->Cell(30,10,'Title',1,0,'C');
//Line break
$this->Ln(20);
}

//Page footer
function Footer()
{
//Position at 1.5 cm from bottom
$this->SetY(-15);
//Arial italic 8
$this->SetFont('Arial','I',8);
//Page number
$this->Cell(0,10,'Page '.$this->PageNo().'/{nb}',0,0,'C');
}
}

//Instanciation of inherited class
$pdf=new PDF();
$pdf->AliasNbPages();
$pdf->AddPage();
$pdf->SetFont('Times','',12);
for($i=1;$i<=40;$i++)
$pdf->Cell(0,10,'Printing line number '.$i,0,1);
$pdf->Output('Test.pdf','I');
?>

$html ='
<style>
.footer_end { position: absolute;
 overflow: visible;
 left: 40px;
 right: 40px;
 bottom: 40px;
 border: 0px;
}
</style>
';



$html .='<div class="footer_end">ข้อความส่วนท้ายกระดาษ</div>';