sergey24,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(function() {
$( ".item" ).each(function() {
var el = $(this), page = el.data("page");
el.toggle(page >=1 && page <= 20)
});
});
</script>
</head>
<body>
<div class="item" data-page="10">10</div>
<div class="item" data-page="10">10</div>
<div class="item" data-page="25">25</div>
</body>
</html>