base32.js

window.base32 = (function () {
    var b32 = function () {
        this.map = {};
        this.reverse = {};
        for(var i = 0;i<32;i++){
            var str = '';
            for(var k =4;k>=0;k--){
                str += (i&(1 << k))?'1':'0';
            }
            this.map[this.chars[i]]=str;
            this.reverse[str]=this.chars[i];
        }
    };
    b32.prototype = {
        chars : '0123456789abcdefghijklmnopqrstuv',
        fromBinary: function (s) {
            var pad = '';
            var ret = '';
            for (var i = 0, z = (5 - s.length % 5) % 5; i < z; i++)pad += '0';
            var seed = pad + s;
            for (var k = 0, x = seed.length / 5; k < x; k++) {
                ret+=this.reverse[seed.substr(k*5,5)];
            }
            return ret;
        },
        toBinary: function (s) {
            var ret = '';
            for (var i = 0, z = s.length; i < z; i++){
                ret+=this.map[s[i]];
            }
            return ret.replace(/^0*/,'');
        }
    };
    return new b32();
})();

window.onload = function(){
    var bin = '0001010110010001010100010010101001010101';
    var b32str = base32.fromBinary('1'+bin);
    var bin2 = base32.toBinary(b32str).substr(1);
    console.log(bin);
    console.log(b32str);
    console.log(bin2);
};