<div id="main1" style="color:blue" onclick="document.all.child1.style.display=(document.all.child1.style.display =='none')?'':'none'" >
+ 主目录1</div>
<div id="child1" style="display:none">
&nbsp;
<a href="#"><font size="2">- 子目录1</font></a><font size="2"> <br>
&nbsp;
<a href="#">- 子目录2</a> <br>
&nbsp;
<a href="#">- 子目录3</a> <br>
&nbsp; </font>
<a href="#"><font size="2">- 子目录4</font></a>
</div>
<div id="main2" style="color:blue" onclick="document.all.child2.style.display=(document.all.child2.style.display =='none')?'':'none'" >
+ 主目录2 </div>
<div id="child2" style="display:none; width:985; height:48">
&nbsp;
<a href="#"><font size="2">- 子目录1</font></a><font size="2"> <br>
&nbsp;
<a href="#">- 子目录2</a> <br>
&nbsp;
<a href="#">- 子目录3</a> </font>
</div>