JavaScript Base64コーディング

2014年8月3日

JavaScriptコード：
function Encode64(value) {
value = escape(value);
var output = “";
var chr1, chr2, chr3 = “";
var enc1, enc2, enc3, enc4 = “";
var i = 0;

do {
chr1 = value.charCodeAt(i );
chr2 = value.charCodeAt(i );
chr3 = value.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);
chr1 = chr2 = chr3 = “";
enc1 = enc2 = enc3 = enc4 = “";
} while (i < value.length);

return output;
}