请问怎样把网页分成4个小框?
如下只能把网页分成3个小框,我要把最上面的那个框也分为左右两个框,请问怎样实现?

<frameset   rows= "40,* "   frameborder= "0 "     marginwidth= "0 "   marginheight= "0 "   leftmargin= "0 "   topmargin= "0 ">
              <frame   name= "top "   src= "xx.html "     scrolling= "NO ">  
                <frameset   cols= "220,* "   frameborder= "1 "   >
                <frame   name= "detail "   src= "sss.html ">
                <frame   name= "main "     src= "kdk.html ">
                </frameset>

      </frameset>

------解决方案--------------------
<frameset rows= "40,* " frameborder= "0 " marginwidth= "0 " marginheight= "0 " leftmargin= "0 " topmargin= "0 ">
<frameset cols= "220,* " frameborder= "1 " >
<frame name= "top1 " src= "xx.html ">
<frame name= "top2 " src= "xx.html ">
</frameset>
<frameset cols= "220,* " frameborder= "1 " >
<frame name= "detail " src= "sss.html ">
<frame name= "main " src= "kdk.html ">
</frameset>
</frameset>