function convert($type='pdf')

        {

            $filename=time();

            $url=$this->input->get("url");

            if($type=='pdf')

            {

                $filename="F:/upload/tmp/".$filename.".pdf";

                exec("F:/home/phptool/wkhtmltopdf-i386 $url $filename");

                header('Content-Type: application/pdf');

            }

            elseif($type=='image')

            {

                $filename="upload/tmp/".$filename.".jpg";

                exec("/home/phptool/wkhtmltoimage-i386 $url $filename");

                header('Content-Type: image/jpeg');

            }

            header('Pragma: public');

            header('Expires: 0');

            header('Cache-Control: must-revalidate, post-check=0, pre-check=0');

            header('Content-Transfer-Encoding: binary');

            header('Content-Length: '.filesize($filename));

            readfile("$filename");

        }