This will hide the div after 1 second (1000 milliseconds).
setTimeout(function() {
$('#mydiv').fadeOut('fast');
}, 1000); // <-- time in milliseconds
#mydiv{
width: 100px;
height: 100px;
background: #000;
color: #fff;
text-align: center;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="mydiv">myDiv</div>
If you just want to hide without fading, use hide()
.