console 命令行工具 X clear
console
<!DOCTYPE html>
<html>
 
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> 
	<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0"/>
    <title>zoom</title>
    <link rel="stylesheet" href="">
    <style type="text/css">
    html,
    body {
        height: 100%;
        width: 100%;
        padding: 0;
        margin: 0;

    }
 
    .box {
        width: 90%;
        height: 90%;
        margin: 10% 5%;
        background: #999;

        position:relative;/*重点*/
    }
 
    #zoomEl {
	    position: absolute;/*重点*/
	    width: 200px;
	    height: 200px;
	    left: calc(50% - 100px);
	    top: calc(50% - 100px);
	    background-color: red;
	    background-image: url(./a.png);
	    background-repeat: round;
	    display: inline-block;
	}
    </style>
</head>
 
<body style="background-color: #ddd;    pointer-events: fill;">
    <div class="box">
        <div id="zoomEl">1234444123</div>

        <iframe src ="http://51js.com/" width="100%" height="100%" style="pointer-events: fill;">
            <p>你的浏览器不支持iframes。</p>
            </iframe>
    </div>
 
</body>
 
</html>