js base64加密解密

var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var base64DecodeChars = new Array(
    -, -, -, -, -, -, -, -, -, -, -, -, -, -, -, -,
    -, -, -, -, -, -, -, -, -, -, -, -, -, -, -, -,
    -, -, -, -, -, -, -, -, -, -, -, , -, -, -, ,
    , , , , , , , , , , -, -, -, -, -, -,
    -,  ,  ,  ,  ,  ,  ,  ,  ,  ,  , , , , , ,
    , , , , , , , , , , , -, -, -, -, -,
    -, , , , , , , , , , , , , , , ,
    , , , , , , , , , , , -, -, -, -, -);

function base64encode(str) {
    var out, i, len;
    var c1, c2, c3;

    len = str.length;
    i = ;
    out = "";
    while(i < len) {
    c1 = str.charCodeAt(i++) & 0xff;
    if(i == len)
    {
        out += base64EncodeChars.charAt(c1 >> );
        out += base64EncodeChars.charAt((c1 & 0x3) << );
        out += "==";
        break;
    }
    c2 = str.charCodeAt(i++);
    if(i == len)
    {
        out += base64EncodeChars.charAt(c1 >> );
        out += base64EncodeChars.charAt(((c1 & 0x3)<< ) | ((c2 & 0xF0) >> ));
        out += base64EncodeChars.charAt((c2 & 0xF) << );
        out += "=";
        break;
    }
    c3 = str.charCodeAt(i++);
    out += base64EncodeChars.charAt(c1 >> );
    out += base64EncodeChars.charAt(((c1 & 0x3)<< ) | ((c2 & 0xF0) >> ));
    out += base64EncodeChars.charAt(((c2 & 0xF) << ) | ((c3 & 0xC0) >>));
    out += base64EncodeChars.charAt(c3 & 0x3F);
    }
    return out;
}

function base64decode(str) {
    var c1, c2, c3, c4;
    var i, len, out;

    len = str.length;
    i = ;
    out = "";
    while(i < len) {
    /* c1 */
    do {
        c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
    } while(i < len && c1 == -);
    if(c1 == -)
        break;

    /* c2 */
    do {
        c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
    } while(i < len && c2 == -);
    if(c2 == -)
        break;

    out += String.fromCharCode((c1 << ) | ((c2 & 0x30) >> ));

    /* c3 */
    do {
        c3 = str.charCodeAt(i++) & 0xff;
        if(c3 == )
        return out;
        c3 = base64DecodeChars[c3];
    } while(i < len && c3 == -);
    if(c3 == -)
        break;

    out += String.fromCharCode(((c2 & 0XF) << ) | ((c3 & 0x3C) >> ));

    /* c4 */
    do {
        c4 = str.charCodeAt(i++) & 0xff;
        if(c4 == )
        return out;
        c4 = base64DecodeChars[c4];
    } while(i < len && c4 == -);
    if(c4 == -)
        break;
    out += String.fromCharCode(((c3 & 0x03) << ) | c4);
    }
    return out;
}

function utf16to8(str) {
    var out, i, len, c;

    out = "";
    len = str.length;
    for(i = ; 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 >> ) & 0x0F));
        out += String.fromCharCode(0x80 | ((c >>  ) & 0x3F));
        out += String.fromCharCode(0x80 | ((c >>  ) & 0x3F));
    } else {
        out += String.fromCharCode(0xC0 | ((c >>  ) & 0x1F));
        out += String.fromCharCode(0x80 | ((c >>  ) & 0x3F));
    }
    }
    return out;
}

function utf8to16(str) {
    var out, i, len, c;
    var char2, char3;

    out = "";
    len = str.length;
    i = ;
    while(i < len) {
    c = str.charCodeAt(i++);
    switch(c >> )
    {
      case : case : case : case : case : case : case : case :
        // 0xxxxxxx
        out += str.charAt(i-);
        break;
      case : case :
        // 110x xxxx   10xx xxxx
        char2 = str.charCodeAt(i++);
        out += String.fromCharCode(((c & 0x1F) << ) | (char2 & 0x3F));
        break;
      case :
        // 1110 xxxx  10xx xxxx  10xx xxxx
        char2 = str.charCodeAt(i++);
        char3 = str.charCodeAt(i++);
        out += String.fromCharCode(((c & 0x0F) << ) |
                       ((char2 & 0x3F) << ) |
                       ((char3 & 0x3F) << ));
        break;
    }
    }

    return out;
}

function CharToHex(str) {
    var out, i, len, c, h;
    out = "";
    len = str.length;
    i = ;
    while(i < len)
    {
        c = str.charCodeAt(i++);
        h = c.toString();
        if(h.length < )
            h = "" + h;

        out += "\\x" + h + " ";
        if(i >  && i %  == )
            out += "\r\n";
    }

    return out;
}

function doEncode() {
    var src = document.getElementById('src').value;
    document.getElementById('dest').value = base64encode(utf16to8(src));    //调用这里加密
}

function doDecode() {
    var src = document.getElementById('src').value;
    var opts = document.getElementById('opt');

    if(opts.checked)
    {
        document.getElementById('dest').value = CharToHex(base64decode(src));   //调用这里解密
    }
    else
    {
        document.getElementById('dest').value = utf8to16(base64decode(src));
    }
}
//window.BASE64 = __BASE64;
function ss(){
    return '';
}
 

js  base64加密解密