W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
  <title>Mouse Pointer Position</title>
  <style>
    #app {
      border: black dashed 1px;
      width: 200px;
      padding: 0 20px 20px 20px;
    }
    #app > div {
      width: 160px;
      height: 80px;
      background-color: lightcoral;
      padding: 20px;
    }
    #app span {
      font-weight: bold;
      font-family: 'Courier New', Courier, monospace;
    }
  </style>
</head>
<body>

<h1>Example: Mouse Pointer Position</h1>

<div id="app">
  <p>Move the mouse pointer over the box below:</p>
  <div v-on:mousemove="mousePos">
    <span>xPos: {{ xPos }}</span><br><span>yPos: {{ yPos }}</span>
  </div>
</div>

</body>
</html>