CSS实现二维码扫描的效果

<p class="code-bg">
 <p class="line"></p>
</p>

.code-bg{
	 position: relative; 
	 height: 200px; width: 200px; 
	 margin: 0px auto;/*此处为了居中*/
	 background: url(img/ewm1.jpg) center top no-repeat; /*二维码*/
	}
	.line{ 
	 position: absolute; 
	 left: -80px; 
	 z-index: 2; 
	 height: 3px; width: 360px; 
	 background: url(img/share/dapai.png) no-repeat; /*上下扫的线*/
	 /*动画效果*/
	 animation: myScan 1s infinite alternate; 
	 -webkit-animation: myScan 1s infinite alternate; 
	}
	@keyframes myScan{
	 from { top:0px; }
	 to { top: 197px; }
	}
	-webkit-@keyframes myScan{
	 from { top:0px; }
	 to { top: 197px; }
	}