MPDF类库下载地址：https://download.csdn.net/download/babayao/10592355
require_once 'vendor/autoload.php'; //引入类库文件
$config = [
'mode' => 'utf-8',
'format' => 'WEIXIN',
'default_font_size' => 0,
'default_font' => 'simhei',
'mgl' => 52.5,
'mgr' => 52.5,
'mgt' => 64,
'mgb' => 23,
'mgh' => 38,
'mgf' => 23,
'orientation' => 'P'];
$mpdf = new \Mpdf\Mpdf($config);
//添加页眉和页脚到pdf中
$mpdf->SetHTMLHeader($header);
$mpdf->SetHTMLFooter($footer);
$style = file_get_contents('https://XXX.com/mpdf.css');
// $t0 = microtime(1);
$mpdf->WriteHTML($style, 1);
$mpdf->WriteHTML($page1);
$mpdf->AddPage();
$mpdf->WriteHTML($page2 . $page3 . $page4);
$fileName = $purchaseid . '.pdf';
//输出pdf文件
$mpdf->Output('pdf/' . $fileName, 'I'); //'I'表示在线展示 'D'则显示下载窗口 'F'保存本地文件
