<!DOCTYPE html>
<html>
<head>
<script src="/lib/jquery-1.12.2.min.js"></script>
<script>
$(document).ready(function(){
$(".btn1").click(function(){
$("p").fadeOut(1000, function(){
alert("fadeOut() method is finished!");
});
});
$(".btn2").click(function(){
$("p").fadeIn(1000, function(){
alert("fadeIn() method is finished!");
});
});
});
</script>
</head>
<body>
<p>This is a paragraph.</p>
<button class="btn1">Fade out</button>
<button class="btn2">Fade in</button>
</body>
</html>