stack.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Stack</title>
  </head>
  <body>
    <h1>Hello Stack</h1>
    <script type="text/javascript">
      'use strict'
      console.log('hello');
      debugger;
      function first(x) {
        return second(x * 2)
      }

      function second(x) {
        return third(x + 12)
      }

      function third(x) {
        return x * 3
      }

      let result = first(3)
      console.log(result)
    </script>
  </body>
</html>