in post.php :
$sql = mysql_query("SELECT * FROM posts WHERE active ='0' LIMIT 1") or die (mysql_error());
$row = mysql_fetch_array($sql);
echo $row['sitepost'];
JS :
<script type="text/javascript">
$(document).ready(function(){
$("#yes").click(function(){
$(".post-body").eq(0).load("post.php");
})
})
</script>
HTML :
<div id="yes">YES</div>
<div class="post-body"></div>