Base64转换字符串两种方式
1.引入Base64.js文件使用方式如下
第一种方式引入文件使用方式如下:
var b = new Base64();
//转码
var str = b.encode("admin:admin");
alert("base64 encode:" + str);
//解码
str = b.decode(str);
alert("base64 decode:" + str);
第二种方式函数调用形式使用方式如下:
//要解码的base64
function base64ToString(data) {
/** Convert Base64 data to a string */
var toBinaryTable = [-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, 0, -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 result = '';
var leftbits = 0;
var leftdata = 0;
for (var i = 0; i < data.length; i++) {
var c = toBinaryTable[data.charCodeAt(i) & 0x7f];
var padding = (data.charCodeAt(i) == '='.charCodeAt(0));
if (c == -1) continue;
leftdata = (leftdata << 6) | c;
leftbits += 6;
if (leftbits >= 8) {
leftbits -= 8;
if (!padding)
result += String.fromCharCode((leftdata >> leftbits) & 0xff);
leftdata &= (1 << leftbits) - 1;
}
}
if (leftbits)
throw Components.Exception('Corrupted base64 string');
return result;
}
//字符串转换为base64
function toBase64(data) {
var toBase64Table = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
var base64Pad = '=';
var result = '';
var length = data.length;
var i;
// Convert every three bytes to 4 ascii characters.
for (i = 0; i < (length - 2); i += 3) {
result += toBase64Table[data.charCodeAt(i) >> 2];
result += toBase64Table[((data.charCodeAt(i) & 0x03) << 4) + (data.charCodeAt(i + 1) >> 4)];
result += toBase64Table[((data.charCodeAt(i + 1) & 0x0f) << 2) + (data.charCodeAt(i + 2) >> 6)];
result += toBase64Table[data.charCodeAt(i + 2) & 0x3f];
}
// Convert the remaining 1 or 2 bytes, pad out to 4 characters.
if (length % 3) {
i = length - (length % 3);
result += toBase64Table[data.charCodeAt(i) >> 2];
if ((length % 3) == 2) {
result += toBase64Table[((data.charCodeAt(i) & 0x03) << 4) + (data.charCodeAt(i + 1) >> 4)];
result += toBase64Table[(data.charCodeAt(i + 1) & 0x0f) << 2];
result += base64Pad;
} else {
result += toBase64Table[(data.charCodeAt(i) & 0x03) << 4];
result += base64Pad + base64Pad;
}
}
return result;
}
调用函数解码方式
//调用base64转字符串方式
var result = base64ToString(reader.result);
console.log(result);
//调用字符串转base64方式
var result2 = toBase64(reader.result);
console.log(result2 );