定时显示隐藏

<script type="text/javascript">
    function close2(){
        // $('#a').css('display','none');
        $('#a').hide();
        // alert('message');
    }
    function xianshi2(){
        $('#a').css('display','block');
    }
    setInterval('xianshi2()',10000);
</script>
<div id='a' style="position:fixed;bottom:30px;left:20px;display:none;">
    <div style="text-align:right;">
        <a href="javascript:void(0);" onclick="close2()" ><img src="images/001-1.png" alt="" /></a>
    </div>
    <img src="images/002.png" alt="" />
</div>