1.引用qrcode.js前，去如下位址下載下傳或學習使用
QRCode.js教程位址可參考:http://www.runoob.com/w3cnote/javascript-qrcodejs-library.html
Github 位址：
https://github.com/davidshimjs/qrcodejs2.scanner.html(生成二維碼)
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="">
<meta name="keywords" content="">
<meta name="author" content="webthemez">
<!-- Title -->
<title>test</title>
<script type="text/javascript">
function test(){
// 設定參數方式
var qrcode = new QRCode('qrcode', {
text: 'test.html',
width: 238,//設定二維碼的寬
height: 210,//設定二維碼的高
colorDark : '#000000',
colorLight : '#ffffff',
correctLevel : QRCode.CorrectLevel.H
});
$("#qrcode").show();
}
</script>
</head>
<body class="index" id="to-top" onload="test()">
<footer class="footer-section" role="contentinfo">
<div class="container">
<div class="row">
<p><a name="test">手機APP使用者請掃描下方二維碼</a></p>
<div id="qrcode" style="display:none;">
</div>
</div>
</div>
</footer>
<script src="js/jquery-2.1.0.min.js"></script>
<script src="js/qrcode.js"></script>
</body>
</html>
3.test.html(微信掃描時，判斷是否是微信，根據核心判斷，如果是微信跳轉到如下weixin.png圖，同時也是個html頁面，會提示使用在浏覽器中打開，然後點選打開浏覽器直接下載下傳，非微信浏覽器使用者可直接掃描下載下傳）
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
<title>APP下載下傳</title>
<script src="js/jquery-2.1.0.min.js" type="text/javascript" charset="utf-8"></script>
<script language="javascript">
window.onload = function() {
var u = navigator.userAgent;
if (u.indexOf('Android') > -1 || u.indexOf('Linux') > -1) { //安卓手機
// alert("安卓手機");
window.location.href = "apk目錄";
} else if (u.indexOf('iPhone') > -1) { //蘋果手機
// alert("蘋果手機");
window.location.href = "apk目錄";
} else if (u.indexOf('Windows Phone') > -1) { //winphone手機
alert("WindowsPhone暫未推出。");
// window.location.href = "apk目錄";
}else{
window.location.href = "apk目錄";
}
// var vU=JSON.stringify(u);
// alert(vU);
}
$(window).on("load", function() {
var winHeight = $(window).height();
function is_weixin() {
var ua = navigator.userAgent.toLowerCase();
if (ua.match(/MicroMessenger/i) == "micromessenger") {
return true;
} else {
return false;
}
}
var isWeixin = is_weixin();
if (isWeixin) {
$(".weixin-tip").css("height", winHeight);
$(".weixin-tip").show();
}
})
</script>
<style type="text/css">
* {
margin: 0;
padding: 0;
}
a {
text-decoration: none;
}
img {
max-width: 100%;
height: auto;
}
.weixin-tip {
position: fixed;
left: 0;
top: 0;
bottom: 0;
background: rgba(0, 0, 0, 0.8);
filter: alpha(opacity=80);
height: 100%;
width: 100%;
z-index: 100;
}
.weixin-tip p {
text-align: center;
margin-top: 10%;
padding: 0 5%;
}
</style>
</head>
<body>
<div class="weixin-tip">
<p>
<img src="images/weixin.png" alt="微信打開" />
</p>
</div>
</body>
</html> 4.圖檔
weixin.png 
![JavaScript自學筆記【4】函數的聲明與調用目錄二、函數的聲明 三、函數的調用[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)