try this.. :)
set this link of jQuery
<script type="text/javascript" src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
Javascript
$(document).ready(function () {
setTimeout(function () { $("#dialog").fadeIn(); }, 15000)
});
function Close() {
$("#dialog").fadeOut();
}
HTML
<div id="dialog" style="display: none">
<div style="height: 170px">
This is a simple popup
</div>
<div>
<span önclick="Close()">click to Close</span></div>
</div>
CSS
#dialog
{
height: 200px;
width: 200px;
background-color: #c8c8c8;
border: 1px solid black;
position: fixed;
top: 50%;
margin-top: -100px;
left: 50%;
margin-left: -100px;
display: none;
padding: 20px;
}