Create Observable from event

<!DOCTYPE html>
<html>

  <head>
    <script data-require="rxjs@5.0.0-beta.7" data-semver="5.0.0-beta.7" src="https://npmcdn.com/rxjs@5.0.0-beta.7/bundles/Rx.umd.js"></script>
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
  </head>

  <body>
    <h1>Create Observable</h1>
    <button>Click me</button>
  </body>

</html>

// Code goes here
window.onload = function() {
  var input = document.querySelector('button');
  
  var observable = Rx.Observable.fromEvent(input,  'click');
  
  observable.subscribe((event) => {
    console.log('Observable: ', event);
  });

  input.addEventListener('click', (event) => {
    console.log('Event listener: ', event);
  });
}

/* Styles go here */