w3 schools

   
<button onclick="myFunction()">Click Me!</button>


<script>

function myFunction() {

  var x = document.getElementById("demo");

  x.style.fontSize = "25px"; 

  x.style.color = "red"; 
}

</script>
    
   

 Name: <input type="text" name="name">

 E-mail: <input type="text" name="email">
Website: <input type="text" name="website">
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
 

 Name: <input type="text" name="name">

 E-mail: <input type="text" name="gdgdfgfdgfdg">
Website: <input type="text" name="website">
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
 

MDN vs W3S: Civil War!