js实现bota

js自带bota，但某环境并不支持，下面为复现算法

var _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="

// private method for UTF-8 encoding
function _utf8_encode (string) { 
   
    string = string.replace(/\r\n/g,"\n");
    var utftext = "";
    for (var n = 0; n < string.length; n++) { 
   
        var c = string.charCodeAt(n);
        if (c < 128) { 
   
            utftext += String.fromCharCode(c);
        } else if((c > 127) && (c < 2048)) { 
   
            utftext += String.fromCharCode((c >> 6) | 192);
            utftext += String.fromCharCode((c & 63) | 128);
        } else { 
   
            utftext += String.fromCharCode((c >> 12) | 224);
            utftext += String.fromCharCode(((c >> 6) & 63) | 128);
            utftext += String.fromCharCode((c & 63) | 128);
        }

    }
    return utftext;
}

// private method for UTF-8 decoding
function _utf8_decode (utftext) { 
   
    var string = "";
    var i = 0;
    var c = 0;
    var c1 = 0;
    var c2 = 0;
    var c3 = 0;
    while ( i < utftext.length ) { 
   
        c = utftext.charCodeAt(i);
        if (c < 128) { 
   
            string += String.fromCharCode(c);
            i++;
        } else if((c > 191) && (c < 224)) { 
   
            c2 = utftext.charCodeAt(i+1);
            string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
            i += 2;
        } else { 
   
            c2 = utftext.charCodeAt(i+1);
            c3 = utftext.charCodeAt(i+2);
            string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
            i += 3;
        }
    }
    return string;
}

// public method for encoding
function encode (input) { 
   
    var output = "";
    var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
    var i = 0;
    input = _utf8_encode(input);
    while (i < input.length) { 
   
        chr1 = input.charCodeAt(i++);
        chr2 = input.charCodeAt(i++);
        chr3 = input.charCodeAt(i++);
        enc1 = chr1 >> 2;
        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
        enc4 = chr3 & 63;
        if (isNaN(chr2)) { 
   
            enc3 = enc4 = 64;
        } else if (isNaN(chr3)) { 
   
            enc4 = 64;
        }
        output = output +
        _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
        _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
    }
    return output;
}

今天的文章js实现bota分享到此就结束了，感谢您的阅读。