JavaScript 的 BASE64 算法
var BASE64={ enKey: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/', deKey: new Array( -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 ), encode: function(src){ //用一个数组来存放编码后的字符，效率比用字符串相加高很多。 var str=new Array(); var ch1, ch2, ch3; var pos=0; //每三个字符进行编码。 while(pos+3<=src.length){ ch1=src.charCodeAt(pos++); ch2=src.charCodeAt(pos++); ch3=src.charCodeAt(pos++); str.push(this.enKey.charAt(ch1>>2), this.enKey.charAt(((ch1<<4)+(ch2>>4))&0x3f)); str.push(this.enKey.charAt(((ch2<<2)+(ch3>>6))&0x3f), this.enKey.charAt(ch3&0x3f)); } //给剩下的字符进行编码。 if(pos<src.length){ ch1=src.charCodeAt(pos++); str.push(this.enKey.charAt(ch1>>2)); if(pos<src.length){ ch2=src.charCodeAt(pos); str.push(this.enKey.charAt(((ch1<<4)+(ch2>>4))&0x3f)); str.push(this.enKey.charAt(ch2<<2&0x3f), '='); }else{ str.push(this.enKey.charAt(ch1<<4&0x3f), '=='); } } //组合各编码后的字符，连成一个字符串。 return str.join(''); }, decode: function(src){ //用一个数组来存放解码后的字符。 var str=new Array(); var ch1, ch2, ch3, ch4; var pos=0; //过滤非法字符，并去掉'='。 src=https://www.jb51.net/src.replace(/[^A-Za-z0-9\+\/]/g, ''); //decode the source string in partition of per four characters. while(pos+4<=src.length){ ch1=this.deKey[src.charCodeAt(pos++)]; ch2=this.deKey[src.charCodeAt(pos++)]; ch3=this.deKey[src.charCodeAt(pos++)]; ch4=this.deKey[src.charCodeAt(pos++)]; str.push(String.fromCharCode( (ch1<<2&0xff)+(ch2>>4), (ch2<<4&0xff)+(ch3>>2), (ch3<<6&0xff)+ch4)); } //给剩下的字符进行解码。 if(pos+1<src.length){ ch1=this.deKey[src.charCodeAt(pos++)]; ch2=this.deKey[src.charCodeAt(pos++)]; if(pos<src.length){ ch3=this.deKey[src.charCodeAt(pos)]; str.push(String.fromCharCode((ch1<<2&0xff)+(ch2>>4), (ch2<<4&0xff)+(ch3>>2))); }else{ str.push(String.fromCharCode((ch1<<2&0xff)+(ch2>>4))); } } //组合各解码后的字符，连成一个字符串。 return str.join(''); } };
使用方法：
var str='hello world!'; var enstr=BASE64.encode(str); alert(enstr); var destr=BASE64.decode(enstr); alert(destr);
收藏的Base64编码/解码.在一个外国网站看到的.不过对中文不支持.
自己加入了escape,.对中文也支持了.
先用escape()对中文进行编码.然后再进行base64编码.
解码时,再加入()对中文进行解码.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title> New Document </title> <meta content="EditPlus"> <meta content=""> <meta content=""> <meta content=""> <script type='text/javascript'> var keyStr = "ABCDEFGHIJKLMNOP" + "QRSTUVWXYZabcdef" + "ghijklmnopqrstuv" + "wxyz0123456789+/" + "="; function encode64(input) { input = escape(input); var output = ""; var chr1, chr2, chr3 = ""; var enc1, enc2, enc3, enc4 = ""; var i = 0; do { chr1 = input.charCodeAt(i++); chr2 = input.charCodeAt(i++); chr3 = input.charCodeAt(i++); enc1 = chr1 >> 2; enc2 = ((chr1 & 3) << 4) | (chr2 >> 4); enc3 = ((chr2 & 15) << 2) | (chr3 >> 6); enc4 = chr3 & 63; if (isNaN(chr2)) { enc3 = enc4 = 64; } else if (isNaN(chr3)) { enc4 = 64; } output = output + keyStr.charAt(enc1) + keyStr.charAt(enc2) + keyStr.charAt(enc3) + keyStr.charAt(enc4); chr1 = chr2 = chr3 = ""; enc1 = enc2 = enc3 = enc4 = ""; } while (i < input.length); return (output); } function decode64(input) { var output = ""; var chr1, chr2, chr3 = ""; var enc1, enc2, enc3, enc4 = ""; var i = 0; // remove all characters that are not A-Z, a-z, 0-9, +, /, or = var base64test = /[^A-Za-z0-9\+\/\=]/g; if (base64test.exec(input)) { alert("There were invalid base64 characters in the input text.\n" + "Valid base64 characters are A-Z, a-z, 0-9, '+', 'https://www.jb51.net/', and '='\n" + "Expect errors in decoding."); } input = input.replace(/[^A-Za-z0-9\+\/\=]/g, ""); do { enc1 = keyStr.indexOf(input.charAt(i++)); enc2 = keyStr.indexOf(input.charAt(i++)); enc3 = keyStr.indexOf(input.charAt(i++)); enc4 = keyStr.indexOf(input.charAt(i++)); chr1 = (enc1 << 2) | (enc2 >> 4); chr2 = ((enc2 & 15) << 4) | (enc3 >> 2); chr3 = ((enc3 & 3) << 6) | enc4; output = output + String.fromCharCode(chr1); if (enc3 != 64) { output = output + String.fromCharCode(chr2); } if (enc4 != 64) { output = output + String.fromCharCode(chr3); } chr1 = chr2 = chr3 = ""; enc1 = enc2 = enc3 = enc4 = ""; } while (i < input.length); return (output); } function aa(){ var str='中国'; var enstr=encode64(str); alert(enstr); var destr=decode64(enstr); alert(destr); } </script> </head> <body> <input type="button"> </body> </html>