HTML 前端JS生成二维码 导出二维码

<script src="~/Content/lib/ewm/jquery.qrcode.js"></script>
<script src="~/Content/lib/ewm/utf.js"></script>


        <div id="ewmdiv" style="margin-left:35%;"></div>
        <a onclick="dcEWM()" style="margin-left: 20%;">导出二维码</a>

<script type="text/javascript">
    var ewm = "二维码内容";
    function init(url) {
        $("#ewmdiv").html("");
      $("#ewmdiv").qrcode({
       render: "canvas",
          text: url,
           200,
          height: 200,
       background: "#ffffff",       //二维码的后景色
       foreground: "#000000"//,        //二维码的前景色
       src: '/img/ewm.png'             //二维码中间的图片
       });
     }
    init(ewm);



    var name="二维码名称";
    function dcEWM() {
        init(ewm);
        var now =getDate();
        var img = document.getElementById("ewmdiv").getElementsByTagName("canvas");
        var alink = document.createElement("a");
        alink.href = img[0].toDataURL("image/png");
        alink.download = name + now + ".png";
        alink.click();
    }

    function getDate() {
        var myDate = new Date();
        //获取当前年
        var year = myDate.getFullYear();
        //获取当前月
        var month = myDate.getMonth() + 1;
        //获取当前日
        var date = myDate.getDate();
        var h = myDate.getHours(); //获取当前小时数(0-23)
        var m = myDate.getMinutes(); //获取当前分钟数(0-59)
        var s = myDate.getSeconds();
        //获取当前时间
        now = year + "" + month + date + h + m + s;
    }
</script>