<div id="d1">
<div id="d2">选课</div>
<div id="d3">
<table cellpadding="0" cellspacing="8">
<tr>
<td>可选课程</td>
<td> </td>
<td>选择课程</td>
</tr>
<tr>
<td>
<select id="s1" name="s1" style="width:150px; height:220px;" multiple="multiple">
<option value="zsf">嵌入式开发</option>
<option value="xrr">中间件</option>
<option value="hh">图形处理</option>
</select>
</td>
<td>
<p><input id="b1" type="button" class="s1" value="-->" /></p>
<p><input type="button" id="b2" class="s1" value="-->>" /></p>
<p><input type="button" id="b3" class="s1" value="<--" /></p>
<p><input type="button" id="b4" class="s1" value="<<--" /></p>
</td>
<td><select id="s2" name="s2" style="width:150px;height:220px;" multiple="multiple"></select></td>
</tr>
</table>
</div>
</div>