<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style>
html, body {
height: 100%;
}
body {
margin: 0;
}
div {
width: 100%;
height: 284px;
background: orange;
position: absolute;
}
</style>
</head>
<body>
<button>Жми</button>
<div></div>
<script src="https://code.jquery.com/jquery-2.1.4.js"></script>
<script>
var div = $('div'), baseHeight = div.height();
$('button').click(function() {
div.animate({
height: (div.height() == baseHeight ? '100%' : baseHeight)
});
});
</script>
</body>
</html>