function explode(url, part) {
  let urlParts = url.replace('http://','').replace('https://','').split(/[/?#]/);
  return urlParts[part];
}

let url = 'http://scratch99.com/web-development/javascript/',
    domain = explode(url, 0),
    dir = explode(url, 1),
    subdir = explode(url, 2)

console.log(domain);
console.log(dir);
console.log(subdir);