<style type="text/css"> 
.eweima{ 
width:200px; 
height:200px; 
margin:auto; 

} 
</style> 
<div class="eweima"> 
<script type="text/javascript"> 
document.write("<img src=http://www.mamicode.com/"https://chart.googleapis.com/chart?cht=qr&chs=500x500&choe=UTF-8&chld=L|2&chl="); title="" 
document.write(window.location.href); 
document.write("\" width=\"200\" height=\"200\" alt=\"二维码\"/>"); 
</script>	
</div>