打开及关闭javascript代码

这样的代码已用了好多次，也进行了改进，可后来都忘记了，用起来还得找，浪费了时间。
javascript:

    <script language="JavaScript" type="text/javascript">
    //start
    var old_menu = ''; 
    var old_cell = ''; 
    function menuclick( submenu ,cellbar) 
    { 
        if( old_menu != submenu )
        { 
            if( old_menu !='' )
            { 
            old_menu.style.display = 'none'; 
            } 
            submenu.style.display = 'block'; 
            old_menu = submenu; 
            old_cell = cellbar; 
        }
        else{ 
            submenu.style.display = 'none'; 
            old_menu = ''; 
            old_cell = ''; 
        } 
    }
    //end
</script>

用到的一些代码：

            //start
            function chbgcolor(link)
            {
                link.style.backgroundColor='#E8CBF8';
            }
            function bkbgcolor(link){
                link.style.backgroundColor='#F7EAFE';
            }
            //end
            
           function showDiv(img,div)
            {
               var img = document.getElementById(img);
               var div = document.getElementById(div);
               var picName = img.src;
                picName = picName.substring(picName.lastIndexOf("/")+1);
               if (picName.toLowerCase() == "close.gif")
                {
                   div.style.display ="block";
                    img.src = "images/open.gif";
               }
                else
               {
                   div.style.display ="none";
                    img.src = "images/close.gif";
               }
            }

            //start
            var old_menu = ''; 
            var old_cell = ''; 
            function menuclick(img,submenu,cellbar) 
            { 
                if( old_menu != submenu )
                { 
                    if( old_menu !='' )
                    { 
                    img.title="打开";
                    img.src="images/opend.gif";
                    old_menu.style.display = 'block'; //
                    } 
                    img.title="关闭";
                    img.src="images/opend.gif";
                    submenu.style.display = 'block'; 
                    old_menu = submenu; 
                    old_cell = cellbar; 
                }
                else
                { 
                    img.title="关闭";
                    img.src="images/closed.gif";
                    submenu.style.display = 'none'; 
                    old_menu = ''; 
                    old_cell = ''; 
                } 
            }
            //end
                     function showDiv(img,div)
           {
               var img = document.getElementById(img);
               var div = document.getElementById(div);
               var picName = img.src;
               picName = picName.substring(picName.lastIndexOf("/")+1);
               if (picName.toLowerCase() == "close.gif")
               {
                   div.style.display ="block";
                   img.src = "images/opend.gif";
               }
               else
               {
                    div.style.display ="none";
                    img.src = "images/closed.gif";
               }
               
              } 
            function switchBar(obj)
            {
                if (displayBar)
                {
                    obj.src="images/opend.gif";
                    obj.title="打开";
                }else{
                    obj.src="images/closed.gif";
                    obj.title="关闭";
                }
            } 

aspx:

<asp:Repeater ID="ListReapter" runat="server">
      <HeaderTemplate>
  <table width="98%" border="0" align="center" cellpadding="2" cellspacing="1" bgcolor="#CCCCCC">
    <tr class="usertithead">
      <td width="5%" height="25" align="center">&nbsp;<strong>序号</strong></td>
      <td width="46%" height="25">&nbsp;<strong>产品类别</strong></td>
      <td width="49%">&nbsp;<strong>角色对应用户</strong>&nbsp;</td>
    </tr>
    </HeaderTemplate><ItemTemplate>
    <tr bgcolor="#FFFFFF" onmouseout="this.style.backgroundColor='#FFFFFF'" onmouseover="this.style.backgroundColor='#EEEEEE'">
      <td height="25" align="center">&nbsp;<%# Eval("id")%></td>
      <td height="25"><%# Eval("ptnames").ToString() + "(" + Eval("ptypes").ToString() + ")" + "_" + Eval("chitype").ToString()%></td>
      <td id="bar<%# Eval("id")%>">
      <img src="images/button_view.gif" alt="Browse Accessories" width="54" height="14" border="0"  style="cursor:hand"
      onclick="menuclick(submenu<%# Eval("id")%>,bar<%# Eval("id")%>)"
      onMouseover="this.src='images/button_viewOn.gif'" onMouseout="this.src='images/button_view.gif'"/></td>
    </tr>
    <tr id="submenu<%# Eval("id")%>" bgcolor="#FFFFFF" style="display: none">
      <td height="25" colspan="3">
      <asp:Repeater ID="myReapter" runat="server">
      <HeaderTemplate>
      <table width="100%" border="0" align="center" cellpadding="1" cellspacing="1" bgcolor="#999999">
        <tr>
          <td width="5%" height="25" align="center" bgcolor="#DDDDDD"><strong>序号&nbsp;</strong></td>
          <td width="23%" bgcolor="#DDDDDD"><strong>角色&nbsp;</strong></td>
          <td width="72%" bgcolor="#DDDDDD"><strong>&nbsp;用户</strong></td>
        </tr>
        </HeaderTemplate><ItemTemplate>
        <tr bgcolor="#FFFFFF" onmouseout="this.style.backgroundColor='#FFFFFF'" onmouseover="this.style.backgroundColor='#FFFFCC'"> 
         <td height="25" align="center"><%# Eval("id")%></td>
          <td>&nbsp;<%# Eval("rolename").ToString() + "(" + Eval("id").ToString()+")"%></td>
          <td>&nbsp;<%# UserRoles(Eval("id").ToString())%></td>
        </tr>
        </ItemTemplate>
        <FooterTemplate>
      </table></FooterTemplate></asp:Repeater></td>
    </tr>
    </ItemTemplate>
        <FooterTemplate>
  </table>
  </FooterTemplate></asp:Repeater>