Untitled

<!DOCTYPE html>
<html>

<head>
  <meta name="viewport" content="width=device-width, user-scalable=no" />
  <style>
    html {
      height: 100%;
      width: 100%;
    }
    body {
      height: 2000px;
      width: 100%;
      margin: 0px;
      padding: 0px;
    }

    div.bar {
      width: 20px;
      top: 0px;
      box-sizing: border-box;
      border: 3px solid purple;
    }

    .fixedpercent {
      position: fixed;
      height: 100%;
      background-color: lightsteelblue;
    }

    .fixedvh {
      position: fixed;
      height: 100vh;
      background-color: lightskyblue;
    }

    .abspercent {
      position: absolute;
      height: 100%;
      background-color: darksalmon;
    }

    .absvh {
      position:absolute;
      height: 100vh;
      background-color: coral;
    }

    .textfixed {
      width: 600px;
      height: 20px;
      padding: 0px 20px;
      transform: rotate(90deg);
      transform-origin: left bottom 0;
    }

    .textabs {
      width: 600px;
      height: 20px;
      padding: 0px 120px;
      transform: rotate(90deg);
      transform-origin: left bottom 0;
    }

    #console {
      position: fixed;
      top: 10px;
      left: 10px;
    }

    #fixedbottom {
      position: fixed;
      bottom: 0;
      left: 0;
      width: 50%;
      height: 25px;
      background-color: green;
    }
  </style>
  <script>
    let count = 0;
    function resized() {
      document.getElementById("innerHight").textContent = window.innerHeight;
      document.getElementById("clientHeight").textContent = document.documentElement.clientHeight;
      document.getElementById("count").textContent = ++count;
    }
    var fullscreen = false;
    addEventListener("load", function() {
      document.documentElement.addEventListener("click", function() {
        if (fullscreen)
          document.webkitExitFullscreen();
        else
          document.documentElement.webkitRequestFullscreen();

        fullscreen = !fullscreen;
      });
    });
  </script>
</head>

<body onresize="resized()">

<div style="right: 0px" class="bar fixedpercent"><div class="textfixed">percentage-based position:fixed</div></div>
<div style="right: 25px" class="bar fixedvh"><div class="textfixed">viewport-unit position:fixed</div></div>
<div style="right: 50px" class="bar abspercent"><div class="textabs">percentage-based position:absolute</div></div>
<div style="right: 75px" class="bar absvh"><div class="textabs">viewport-unit position:absolute</div></div>
<div id="console">
  <dl>
    <td>window.innerHeight</td><dd id="innerHight"></dd>
    <td>documentElement.clientHeight</td><dd id="clientHeight"></dd>
    <td>Event count</td><dd id="count"></dd>
  </dl>
</div>
<div id="fixedbottom"></div>
</body>
</html>