JS生成并下载二维码的实现方法

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 
<title>js_canvas_download</title> 
<script type='text/javascript' src='http://cdn.staticfile.org/jquery/2.1.1/jquery.min.js'></script> 
<script type="text/javascript" src="http://cdn.staticfile.org/jquery.qrcode/1.0/jquery.qrcode.min.js"></script> 
</head> 
<body> 
<div id="qrcode"></div> 
<a id="download" download="qrcode.jpg"></a> 
<button id="save">save</button> 
</body> 
</html> 
<script> 
jQuery('#qrcode').qrcode({width: 500,height: 500,text: "http://www.baidu.com"}); 
$("#save").click(function(){ 
var canvas = $('#qrcode').find("canvas").get(0); 
var url = canvas.toDataURL('image/jpeg'); 
$("#download").attr('href', url).get(0).click(); 
return false; 
}); 
</script>