title: Difference between layerX and offsetX in JavaScript
body: <p>There are different co-ordinate system for JavaScript, such as e.clientX, e.screenX.</p>
  
  <p>I understand those two well, but there are some like e.layerX and e.offsetX. These two are not very clear to me. </p>
  
  <p>Can someone explain those two co-ordinates for me?</p>