JS生成二维码

<script type="text/javascript" src="${ctxStatic}/wx/js/jquery.qrcode.min.js"></script>window.onload =function(){    function utf16to8(str) {        var out, i, len, c;        out = "";        len = str.length;        for (i = 0; i < len; i++) {            c = str.charCodeAt(i);            if ((c >= 0x0001) && (c <= 0x007F)) {                out += str.charAt(i);            } else if (c > 0x07FF) {                out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));                out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));                out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));            } else {                out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));                out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));            }        }        return out;    }    $("#qrcode").qrcode({        render: "canvas", //table方式        width: 125, //宽度        height: 125, //高度        text: utf16to8('${ewm}'),    });}