index.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">

  <link rel="stylesheet" href="css/main.css">
  <title>Harry Potter World / AbracadabraHacks</title>
</head>
<body style="display: block;
">

  <video autoplay loop id="myVideo">
    <source src="assets/video_BG.mp4" type="video/mp4">
  </video>

  <div class="main-container">
    <h1>
      Welcome to the world of wizards
    </h1>
    <a href="pages/home.html">
      <button class="offset">
        Start
      </button>
    </a>
  </div>
  <script>
    // Get the video
    var video = document.getElementById("myVideo");

    // Get the button
    // var btn = document.getElementById("myBtn");

    // Pause and play the video, and change the button text
    function myFunction() {
      if (video.paused) {
        video.play();
      }
    }
    
</script>
</body>
</html>