JS：
var StringUtil = new function()
{
this.Base64Encode = function(str)
{
return base64encode(utf16to8(str));
};
this.Base64Decode = function(str)
{
return utf8to16(base64decode(str))
};
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);
var base64encode = function(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;
};
var base64decode = function(str)
{
var c1, c2, c3, c4;
var i, len, out;
len = str.length;
i = 0;
out = "";
while (i < len)
{
do
{
c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
} while (i < len && c1 == -1);
if (c1 == -1)
break;
do
{
c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
} while (i < len && c2 == -1);
if (c2 == -1)
break;
out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));
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));
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;
};
var utf16to8 = function(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;
};
var utf8to16 = function(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:
out += str.charAt(i - 1);
break;
case 12: case 13:
char2 = str.charCodeAt(i++);
out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
break;
case 14:
char2 = str.charCodeAt(i++);
char3 = str.charCodeAt(i++);
out += String.fromCharCode(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0));
break;
}
}
return out;
}
}
ASP.NET C#代码
/// <summary>
/// Base64 (UTF-8) 编码/解码。
/// </summary>
public class Base64
{
/// <summary>
/// 解码。
/// </summary>
/// <param name="base64Str"></param>
/// <returns></returns>
public static string Decode(string base64Str)
{
return System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(base64Str));
}
/// <summary>
/// 编码。
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static string Encode(string utf8Str)
{
return Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(utf8Str));
}
}
