问显示,稳藏代码怎能么写,hookee() 还在吗
<script>
var   oldobj   =   null;
var   oldtd   =   null;
function   show(n){
    var   obj   =   document.getElementById( "t "   +   n);
    var   td   =   document.getElementById( "td "   +   n);
    if   (oldobj!=null   &&   oldobj   !=   obj)   oldobj.style.display= "none ";
    if   (oldtd!=null   &&   oldtd   !=   td)   oldtd.style.backgroundImage= "url(none) ";
    obj.style.display= "block ";
    td.style.backgroundImage= "url(bg "   +   n   +   ".gif) ";
    oldobj   =   obj;
    oldtd   =   td;
}
window.onload=function(){oldobj   =   document.getElementById( "t1 ");}
</script>
<table   width= "350 "   border= "0 "   cellpadding= "0 "   cellspacing= "0 ">
<tr   height= "21 ">
<td   id= "td1 "   style= "background-image:url(bg1.gif); "   onmouseover= "show(1) "> 显示1 </td>
<td   id= "td2 "   style= "background-image:url(none); "   onmouseover= "show(2) "> 显示2 </td>
<td   id= "td3 "   style= "background-image:url(none); "   onmouseover= "show(3) "> "> 显示3 </td>
</tr>
<tr>
<td   colspan= "3 ">
<table   id= "t1 "   style= "display:block; "> <tr> <td   > 显示1内容 </td> </tr> </table>
<table   id= "t2 "   style= "display:none; "> <tr> <td   > 显示2内容 </td> </tr> </table>
<table   id= "t3 "   style= "display:none; "> <tr> <td   > 显示3内容 </td> </tr> </table>
</td>
</tr>
</table>
问题是这样的

1.刚开始是默认 "显示1 ",在表格内显示的是 "显示1内容 "   稳藏 "显示2内容 ", "显示3内容 "
2.点鼠标移到 "显示2 "在表格内显示的是 "显示1内容 "     稳藏 "显示1内容 ", "显示3内容 "
3.当鼠标在移到 "显示3 "时,在表格内显示的是 "显示3内容 "   稳藏 "显示1内容 ", "显示2内容 "
4.当鼠标在移到 "显示1 "时,在表格内显示的是 "显示1内容 "   稳藏 "显示2内容 ", "显示3内容 "


1.刚开始是默认 "显示1 ",在单元格背景色显示的是 "bg1.gif "   稳藏 "bg2.gif ", "bg3.gif "
2.点鼠标移到 "显示2 "在单元格背景色显示的是 "bg2.gif "   稳藏 "bg1.gif ", "bg3.gif "
2.点鼠标移到 "显示3 "在单元格背景色显示的是 "bg3.gif "   稳藏 "bg1.gif ", "bg2.gif "
2.点鼠标移到 "显示1 "在单元格背景色显示的是 "bg1.gif "   稳藏 "bg2.gif ", "bg3.gif "

以上代码是邮网友hookee()   写的,只是还有点小问题,就是刚开始时默认是对的，但当点 "显示2“或 "显示3 "   ,
显示1的背景还在，所以会同时出现二个背景

------解决方案--------------------
<script>
var oldobj = null;
var oldtd = null;
function show(n){
var obj = document.getElementById( "t " + n);
var td = document.getElementById( "td " + n);
if (oldobj!=null && oldobj != obj) oldobj.style.display= "none ";
if (oldtd!=null &&