<!-- language: php -->
<?php
function fetch_data(){
    if (isset($_POST["create_pdf"])){
    require_once("tcpdf/tcpdf.php");

        $obj_pdf = new TCPDF('P' , PDF_UNIT , PDF_PAGE_FORMAT true , 'UTF-8', false);
        $obj_pdf->SetCreator(PDF_CREATOR);
        $obj_pdf->SetTitle("Application");
        $obj_pdf->SetHeaderData('', '' , PDF_HEADER_TITLE, PDF_HEADER_STRING);
        $obj_pdf->setHeaderFont(Array(PDF_FONT_NAME_MAIN, '' , PDF_FONT_SIZE_MAIN));
        $obj_pdf->setFooterFont(Array(PDF_FONT_NAME_DATA, '' , PDF_FONT_SIZE_DATA));
        $obj_pdf->SetDefaultMonospacedFont('helvetica');
        $obj_pdf->SetFooterMargin(PDF_MARGIN_FOOTER);
        $obj_pdf->SetMargins(PDF_MARGIN_LEFT, '5' , PDF_MARGIN_RIGHT);
        $obj_pdf->setPrintHeader(false);
        $obj_pdf->setPrintFooter(false);
        $obj_pdf->SetAutoPageBreak(TRUE, 10);
        $obj_pdf->SetFont('helvetica' , '' , 12);



        $obj_pdf->writeHTML("Hello world!");
        ob_end_clean();
        $obj_pdf->Output("sample.pdf" , "I");

    }
}
 echo "<form method = 'post'>
    <input type='submit' name='create_pdf' value='CreatePDF'/>
 </form>";
 fetch_data();
?>