Try This Editor

Source Code:

<!DOCTYPE html>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
  <script>
     function func() {
       document.getElementById("para").innerHTML = "Hi JS";
     }
  </script>
</head>
<body>
  <p id="para"></p>
  <button type="button" onclick="func()">Click Me</button>
</body>
</html>

Output Preview :

www.c4learn.com/tutorials/ - Try it yourself