<!DOCTYPE html>
<html>
<body>

<p>Click the button to get the tag names of the body element's children.</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
function myFunction() {
  var c = document.body.children;
  var txt = "";
  var i;
  for (i = 0; i < c.length; i++) {
    txt = txt + c[i].tagName + "<br>";
  }

  document.getElementById("demo").innerHTML = txt;
}
</script>

</body>
</html>