base.js

// Arbitrary precision base conversion, WIP

function baxx(str, src_base, dst_base) {
    var number = [], output = "", res = [], quotient, remainder;
    var charset = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    //decode
    for(var i = 0; i < str.length; i++) number[i] = charset.indexOf(str[i]);
    while (number.length) {
        // divide successive powers of dst_base
        quotient = [], remainder = 0;
        for (var i = 0; i != number.length; i++) {
            var accumulator = number[i] + remainder * src_base;
            var digit = accumulator / dst_base | 0; // rounding faster than Math.floor
            remainder = accumulator % dst_base;
            if (quotient.length || digit) quotient.push(digit);
        }
        // the remainder of current division is the next rightmost digit
        res.unshift(remainder);
        // rinse and repeat with next power of dst_base
        number = quotient;
    }
    //encode
    for(var i = 0; i < res.length; i++) output += charset.charAt(res[i]);
    return output;
}

baxx("7DhzpcifUHcRaLDZ24md9e", 62, 16); // ED436E326FC5B328D67BBEC0459A9DB2