大家知道Microsoft的这个效果是如何做出来的吗，50分求解


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<html>
<body>
<form name="form1">
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<tr>
<td>
<a href="" onclick="sh();return false">show/hide</a>
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<tr id="tr1">
<td>&nbsp;Test</td>
</tr>
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</form>
<body>
</html>