index.html

<!Doctype html>
<html>
  <head>
    <title>
    </title>
  </head>
<body>
  <h3>Map iterates through an array and pushes the result of performing a call back on each item in the array to a new array, and returns the new array</h3>
  <div id="map"></div>
  <button id="double">Double the numbers</button>

  <h3>Filter iterates through an array and pushes each item into a new array if it passes a truth test, and finally it returns this new array.  </h3> 
  <div id="filter"></div>
  <button id="onlyEven">Only Even Numbers</button>
<script src='js.js'></script>
</body>
</html>