[Deff]

<script type="text/javascript" src="http://yandex.st/jquery/1.4.4/jquery.min.js"></script>
<style>
div.WRAP{
 width:100px;
 height:30px;
 margin-top:2px;
}
div.n {
 width:100px;
 height:20px;
 border:1px solid red;
 padding:2px 1em;
 background-color:#C4D8EB;
}
</style>
<div class="WRAP">
  <div class="n visible">1</div>
</div>

<div class="WRAP">
  <div class="n hide">2</div>
</div>
<br />
<button class="show-hide">show-hide</button>


<script type="text/javascript">
$('.show-hide').live('click', function() {
  $("div.n").toggleClass("hide");
  $("div.n").toggleClass("visible");
  $("div.n.hide").fadeOut(1500);
  $("div.n.visible").fadeIn(1500)
});

</script>