JS兑现base64加密解密
日期：2014-05-16 浏览次数：20614 次
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<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(
