javascript:
function toBase64(str)
{
    var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    var b64 = "";
    var mask = 0x3f;
    for(var I = 0; I < str.length; I += 3)
    {
        var bits24 = str.charCodeAt(I) << 16 | str.charCodeAt(I + 1) << 8 | str.charCodeAt(I + 2);
        b64 += chars[bits24 >> 18 & mask] + chars[bits24 >> 12 & mask] + chars[bits24 >> 6 & mask] + chars[bits24 & mask];
    }
    return b64;
}
alert(toBase64("Manl"));
void null;