jquery.qrcode.min.js 中文乱码

    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;
    }

    var decodebase = Base64.decode(utf16to8(xxx));