jQuery层次选择器

 <style type="text/css">         table tr td {         width:240px;height:240px;         }         .clasImg {           width:500px;height:200px;         }     </style>     <script src="jquery-1.9.1.js"></script>     <script type="text/javascript">

        $(function () {             $('#Button1').click(function () {               //  $('#img1,#img3,#Button1,#Button2').hide(5000);                 // $('#img1,#img3,#Button1,#Button2').show(5000);

               // $('img').hide(5000);                 //$('img').show(5000);

                $('#img2').removeClass();                 $('#img2').addClass('clasImg');                 $('.imgClass').hide(5000);                 $('.imgClass').show(5000);

            })

            $('#Button2').click(function () {                 //$('#img4').css('width', '300');                 //$('#img4').css('height', '300');

                $('#img1').hide(5000);             })           })     </script>

</head> < body>     <table >         <tr>             <td>                 <img id="img1" alt="" src="images/1.jpg" class="imgClass" />             </td>             <td>                 <img id="img2" alt="" src="images/1.jpg" class="imgClass" />             </td>         </tr>         <tr>             <td>                 <img id="img3" alt="" src="images/1.jpg" class="imgClass" />             </td>             <td>                 <img id="img4" alt="" src="images/1.jpg" class="imgClass" />             </td>         </tr>

    </table>

    <input id="Button1" type="button" value="收缩" />     <input id="Button2" type="button" value="改变大小" />     <input id="Button3" type="button" value="改变DIV" /> < /body> < /html>