<title>jQuery :focus Selector Select Form Element When Focus</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
$(document).ready(function(){
$( ".mydformfocus :focus" ).css("background", "yellow");
<h2>jQuery :focus Selector Select Form Element When Focus</h2>
<form action="#" class="mydformfocus">
<input type="text" name="name" placeholder="Enter your name..."><br><br>
<input type="email" name="email" placeholder="Enter your email..."><br><br>
<button type="button" name="submit">Submit</button>