Cold Observable Example 1

<!DOCTYPE html>
<html>

  <head>
    <script data-require="rxjs@5.1.1" data-semver="5.1.1" src="https://unpkg.com/rxjs@5.1.1/bundles/Rx.min.js"></script>
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
  </head>

  <body>
    <div id="first"></div>
    <button onclick="subscribe1()">Subscribe</button>
    
    <div id="second"></div>
    <button onclick="subscribe2()">Subscribe</button>
  </body>

</html>

const source = Rx.Observable.interval(1000);

function subscribe1() {
  source.subscribe((value) => document.querySelector('#first').innerHTML = value);
}

function subscribe2() {
  source.subscribe((value) => document.querySelector('#second').innerHTML = value);
}

/* Styles go here */