JavaScript base64_encode 函数


JavaScript #base64 #函数2012-04-17 00:31

使用MIME Base64算法编码字符串

function base64_encode (data) {
    
    var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    var o1, o2, o3, h1, h2, h3, h4, bits, i = 0,
        ac = 0,
        enc = "",
        tmp_arr = [];

    if (!data) {
        return data;
    }

    do { // pack three octets into four hexets
        o1 = data.charCodeAt(i++);
        o2 = data.charCodeAt(i++);
        o3 = data.charCodeAt(i++);

        bits = o1 << 16 | o2 << 8 | o3;

        h1 = bits >> 18 & 0x3f;
        h2 = bits >> 12 & 0x3f;
        h3 = bits >> 6 & 0x3f;
        h4 = bits & 0x3f;

        // use hexets to index into b64, and append result to encoded string
        tmp_arr[ac++] = b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4);
    } while (i < data.length);

    enc = tmp_arr.join('');
    
    var r = data.length % 3;
    
    return (r ? enc.slice(0, r - 3) : enc) + '==='.slice(r || 3);

}

用法

base64_encode('yige.org');
返回值

eWlnZS5vcmc=


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