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。