<html><head><script src="https://libs.baidu.com/jquery/2.1.4/jquery.min.js"></script><script>$(document).ready(function(){ $("input").focus(function(){ $(this).css("background-color", "yellow"); }); $("input").blur(function(){ $(this).css("background-color", "green"); });});</script></head><body>Name: <input type="text" name="fullname"><br>Email: <input type="text" name="email"></body></html>