Тогда как вариант...
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
<!--
<link rel="stylesheet" type="text/css" href="tmp.css" />
-->
<style type="text/css">
</style>
<script type="text/javascript">
$(document).ready(function (){
var olist={
6:true,
8:true,
34:true,
88:true
};
$('#category_num > div').each(function (){
var val=this.id;
val=val.split('_')[1];
val=(olist[val])? 'block': 'none';
$('.displaySub').css('display',val);
});
});
</script>
</head>
<body>
<div id="category_num">
<div id="cat_8">
<input type="text" value="..." />
</div>
</div>
<div class="displaySub">Текст</div>
</body>
</html>