JavaScript - Base64 编码解码

以下代码摘自：http://cryptojs.altervista.org/encoding/Base64.html

function base64_encode(str) {

    if (window.btoa) // Internet Explorer 10 and above

    return window.btoa(unescape(encodeURIComponent(str)));

    else {

        // Cross-Browser Method (compressed)

        // Create Base64 Object

        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(/\r\n/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

            }

        }

        // Encode the String

        return Base64.encode(unescape(encodeURIComponent(str)));

    }

}



function base64_decode(str) {

    if (window.atob) // Internet Explorer 10 and above

    return decodeURIComponent(escape(window.atob(str)));

    else {

        // Cross-Browser Method (compressed)

        // Create Base64 Object

        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(/\r\n/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

            }

        }

        // Encode the String

        return decodeURIComponent(escape(Base64.decode(str)));

    }

}

 

普通压缩：

function base64_encode(str){if(window.btoa)return window.btoa(unescape(encodeURIComponent(str)));else{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(/\r\n/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}}return Base64.encode(unescape(encodeURIComponent(str)))}}function base64_decode(str){if(window.atob)return decodeURIComponent(escape(window.atob(str)));else{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(/\r\n/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}}return decodeURIComponent(escape(Base64.decode(str)))}}