<!DOCTYPE html>
<html>
<body onclick="myFunction()">
<p>Click anywhere in the document to display the active element.</p>
<input type="text" value="An input field">
<button>A Button</button>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.activeElement.tagName;
document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>