网页加载前展示广告 - 2秒延迟显示页面内容 - 常规

<html>
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport" />
<title><?php echo $title ?></title>
<body style="margin:0;padding:0;height:100%" scroll=no>
<div style="width:100%;height:100%;position:absolute;z-index:999;background-color:#fff;text-align:center;">
    <img src="广告图片地址" style="width:100%;height:100%;">
</div>
<iframe id="infrm" name="infrm" marginwidth="0" marginheight="0" width="100%" scrolling=auto src="<?php echo $t_url ?>" frameborder="0" height="100%" style="display:none;"></iframe>
<script>
    setTimeout(function(){
        document.getElementById("infrm").style.display = "block";
        document.getElementsByTagName("div")[0].style.display = "none";
    }, 2000);
</script>
</body>
</html>