JavaScript Function Call

<!DOCTYPE html>
<html>
<body>

<h1 id="heading">JavaScript Functions</h1>
<p class="para"> JavaScript Functions 1</p>
<p class="para"> JavaScript Functions 2</p>
<p class="para"> JavaScript Functions 3</p>
<script>
function myFunction(){
  return this;
}
let x = myFunction();
document.write(x.innerWidth);
document.write("<br>");
document.write(this.innerWidth);
</script>
</body>
</html>