js Base64转字符串（两种方式）不能用你打我

Base64转换字符串两种方式

1.引入Base64.js文件使用方式如下

下载Base64.js地址链接

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 );