首先对base64进行定义：
　　var Base64 = {
        _keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
        encode : function(e) {
            var t = "";
            var n, r, i, s, o, u, a;
            var f = 0;
            e = Base64._utf8_encode(e);
            while (f < e.length) {
                n = e.charCodeAt(f++);
                r = e.charCodeAt(f++);
                i = e.charCodeAt(f++);
                s = n >> 2;
                o = (n & 3) << 4 | r >> 4;
                u = (r & 15) << 2 | i >> 6;
                a = i & 63;
                if (isNaN(r)) {
                    u = a = 64
                } else if (isNaN(i)) {
                    a = 64
                }
                t = t + this._keyStr.charAt(s) + this._keyStr.charAt(o)
                        + this._keyStr.charAt(u) + this._keyStr.charAt(a)
            }
            return t
        },
        decode : function(e) {
            var t = "";
            var n, r, i;
            var s, o, u, a;
            var f = 0;
            e = e.replace(/[^A-Za-z0-9+/=]/g, "");
            while (f < e.length) {
                s = this._keyStr.indexOf(e.charAt(f++));
                o = this._keyStr.indexOf(e.charAt(f++));
                u = this._keyStr.indexOf(e.charAt(f++));
                a = this._keyStr.indexOf(e.charAt(f++));
                n = s << 2 | o >> 4;
                r = (o & 15) << 4 | u >> 2;
                i = (u & 3) << 6 | a;
                t = t + String.fromCharCode(n);
                if (u != 64) {
                    t = t + String.fromCharCode(r)
                }
                if (a != 64) {
                    t = t + String.fromCharCode(i)
                }
            }
            t = Base64._utf8_decode(t);
            return t
        },
        _utf8_encode : function(e) {
            e = e.replace(/rn/g, "n");
            var t = "";
            for (var n = 0; n < e.length; n++) {
                var r = e.charCodeAt(n);
                if (r < 128) {
                    t += String.fromCharCode(r)
                } else if (r > 127 && r < 2048) {
                    t += String.fromCharCode(r >> 6 | 192);
                    t += String.fromCharCode(r & 63 | 128)
                } else {
                    t += String.fromCharCode(r >> 12 | 224);
                    t += String.fromCharCode(r >> 6 & 63 | 128);
                    t += String.fromCharCode(r & 63 | 128)
                }
            }
            return t
        },
        _utf8_decode : function(e) {
            var t = "";
            var n = 0;
            var r = c1 = c2 = 0;
            while (n < e.length) {
                r = e.charCodeAt(n);
                if (r < 128) {
                    t += String.fromCharCode(r);
                    n++
                } else if (r > 191 && r < 224) {
                    c2 = e.charCodeAt(n + 1);
                    t += String.fromCharCode((r & 31) << 6 | c2 & 63);
                    n += 2
                } else {
                    c2 = e.charCodeAt(n + 1);
                    c3 = e.charCodeAt(n + 2);
                    t += String.fromCharCode((r & 15) << 12 | (c2 & 63) << 6 | c3
                            & 63);
                    n += 3
                }
            }
            return t
        }
    }  

使用举例：

var name_encode = Base64.encode(name)；

解决js中传值不加密的安全问题，特别是登录页面需要对用户名、密码加密传输到后台，然后在后台解密，完美规避IBM扫描的不加密传输漏洞。