急求WEB大神


<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8"/>
    <title>test</title>
    <style type="text/css">
        #b{ display:none;}
    </style>
    <script type="text/javascript" src="http://lib.sinaapp.com/js/jquery/1.9.1/jquery-1.9.1.js"></script>
</head>
<body>
<div class="a">aaa</div>
<div class="a">aaa222</div>
<div id="b">bbb</div>
<script type="text/javascript">
    $.fn.toggleShow = function(sub, callback){
        var tmp = null;        $(this).on('click', function(){
            if(tmp != this){
                sub.show();
            } else {
                sub.toggle();
            }
            tmp = this;
            callback && callback();
        })
    }    $('.a').toggleShow($('#b'));
</script>
</body>
</html>