focus event

The focus() method attaches an event handler function to an HTML form field.
 
The function is executed when the form field gets focus:

<!DOCTYPE html>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $("input").focus(function(){
    $(this).css("background-color","#999");
  });
  $("input").blur(function(){
    $(this).css("background-color","#FFF");
  });
});
</script>
</head>
<body>

Name: <input type="text" name="fullname"><br>
Email: <input type="text" name="email">

</body>
</html>