JS实现的base64加密解密完整实例

<HTML> <HEAD> <TITLE>Base64</TITLE> <script language=javascript> var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; var base64DecodeChars = 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); <HTML> <HEAD> <TITLE>Base64</TITLE> <script language=JavaScript> var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; var base64DecodeChars = 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); function base64encode(str) {   var out, i, len;   var c1, c2, c3;   len = str.length;   i = 0;   out = "";   while(i < len) { c1 = str.charCodeAt(i++) & 0xff; if(i == len) {    out += base64EncodeChars.charAt(c1 >> 2);    out += base64EncodeChars.charAt((c1 & 0x3) << 4);    out += "==";    break; } c2 = str.charCodeAt(i++); if(i == len) {    out += base64EncodeChars.charAt(c1 >> 2);    out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));    out += base64EncodeChars.charAt((c2 & 0xF) << 2);    out += "=";    break; } c3 = str.charCodeAt(i++); out += base64EncodeChars.charAt(c1 >> 2); out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)); out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6)); out += base64EncodeChars.charAt(c3 & 0x3F);   }   return out; } function base64decode(str) {   var c1, c2, c3, c4;   var i, len, out;   len = str.length;   i = 0;   out = "";   while(i < len) { /* c1 */ do {    c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; } while(i < len && c1 == -1); if(c1 == -1)    break; /* c2 */ do {    c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; } while(i < len && c2 == -1); if(c2 == -1)    break; out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); /* c3 */ do {    c3 = str.charCodeAt(i++) & 0xff;    if(c3 == 61)  return out;    c3 = base64DecodeChars[c3]; } while(i < len && c3 == -1); if(c3 == -1)    break; out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2)); /* c4 */ do {    c4 = str.charCodeAt(i++) & 0xff;    if(c4 == 61)  return out;    c4 = base64DecodeChars[c4]; } while(i < len && c4 == -1); if(c4 == -1)    break; out += String.fromCharCode(((c3 & 0x03) << 6) | c4);   }   return out; } 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; } function utf8to16(str) {   var out, i, len, c;   var char2, char3;   out = "";   len = str.length;   i = 0;   while(i < len) { c = str.charCodeAt(i++); switch(c >> 4) {   case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:    // 0xxxxxxx    out += str.charAt(i-1);    break;   case 12: case 13:    // 110x xxxx  10xx xxxx    char2 = str.charCodeAt(i++);    out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));    break;   case 14:    // 1110 xxxx 10xx xxxx 10xx xxxx    char2 = str.charCodeAt(i++);    char3 = str.charCodeAt(i++);    out += String.fromCharCode(((c & 0x0F) << 12) |     ((char2 & 0x3F) << 6) |     ((char3 & 0x3F) << 0));    break; }   }   return out; } function doit() {   var f = document.f   f.output.value = base64encode(utf16to8(f.source.value))   f.decode.value = utf8to16(base64decode(f.output.value)) } </script> </HEAD> <BODY> <H1>Base64</H1> <FORM> 原码<BR> <TEXTAREA ROWS=4 COLS=60 WRAP="soft"></TEXTAREA><BR><BR> Base64 encode<BR> <TEXTAREA ROWS=4 COLS=60 WRAP="soft"></TEXTAREA><BR><BR> Base64 decode<BR> <TEXTAREA ROWS=4 COLS=60 WRAP="soft"></TEXTAREA><BR><BR> <INPUT TYPE=BUTTON VALUE="转换"> </FORM> </BODY>

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