How can you encode a string to Base64 in JavaScript?

Question

I have a PHP script that can encode a PNG image to a Base64 string.

I\'d like to do the same thing using JavaScript. I know how to open files, but I\'m not sure how

Answer 1

There's a couple of bugs in both implementations of _utf8_decode. c1 and c2 are assigned as global variables due to broken use of the var statement, and c3 is not initialized or declared at all.

It works, but these variables will overwrite any existing ones with the same name outside this function.

Here's a version that won't do this:

// private method for UTF-8 decoding
_utf8_decode : function (utftext) {
    var string = "";
    var i = 0;
    var c = 0, c1 = 0, c2 = 0;

    while ( i < utftext.length ) {

        c = utftext.charCodeAt(i);

        if (c < 128) {
            string += String.fromCharCode(c);
            i++;
        }
        else if((c > 191) && (c < 224)) {
            c1 = utftext.charCodeAt(i+1);
            string += String.fromCharCode(((c & 31) << 6) | (c1 & 63));
            i += 2;
        }
        else {
            c1 = utftext.charCodeAt(i+1);
            c2 = utftext.charCodeAt(i+2);
            string += String.fromCharCode(((c & 15) << 12) | ((c1 & 63) << 6) | (c2 & 63));
            i += 3;
        }

    }
    return string;
}