Anfisunka,
так?
<!DOCTYPE html>
<html>
<head lang="en">
<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>
<meta charset="UTF-8">
<title>
</title>
<style>
div {
border: 1px solid black;
height: 20px;
}
</style>
</head>
<body>
<script>
var div = "<div class='poof' style='top: " + 10 + "px; left: " + 10 + "px'></div>";
$("body").append(div);
setTimeout(function () {
$('.poof')[0].remove();
}, 2000)
</script>
</body>
</html>