多级树的建立

中午实在是困，先把javascipt代码贴上，以后陆续把数据库，VB.NET的代码贴出来
数据库：
CREATE TABLE [dbo].[tree](
 [Nodecode] [varchar](6) COLLATE Chinese_PRC_CI_AS NOT NULL,
 [NodeName] [varchar](30) COLLATE Chinese_PRC_CI_AS NULL,
 [bz] [varchar](30) COLLATE Chinese_PRC_CI_AS NULL,
 [id] [int] NULL,
)
节点的存放规则：
1、一级节点的代码用两位来表示01、02... ...,二级节点四位0101、0102..
2、0101表示01节点下的第一个子节点

    <script>
    
    function hide()
    {
        var tb = document.getElementById("tb");
        var _l = tb.rows.length;
          //alert(tb.rows[0].id.length);
         //tb.rows[5].style.display =  "none";
         for (var i=0; i<_l; i++)
         {
             if(tb.rows[i].id.length != 2)
               {
                 tb.rows[i].style.display =  "none";
             }
         }
    }
    function show(rowid)
    {
        var tb = document.getElementById("tb");
        var _l = tb.rows.length;
        var _rowid = rowid;
          //alert(tb.rows[_rowid].id);
        //alert(rowid.length);
    
         //tb.rows[5].style.display =  "none";
         
         for (var i=0; i<_l; i++)
         {
             if(tb.rows[i].id == rowid)
             {
                 //alert(tb.rows[i].cells[0].children[1].src);
                 if (tb.rows[i].cells[0].children[1].title == "2")
                 {
                     tb.rows[i].cells[0].children[1].src = "../llmis/images/line_01_2.gif";
                     tb.rows[i].cells[0].children[1].title = "1";
                 }                 
                 else 
                 {
                     tb.rows[i].cells[0].children[1].src = "../llmis/images/LINE_01.GIF";
                     tb.rows[i].cells[0].children[1].title = "2";
                 }
             };
             if((tb.rows[i].id.length >= rowid.length+2) && (tb.rows[i].id.substr(0,rowid.length) == rowid))
               {   
                 if(tb.rows[i].style.display ==  "block") 
                 {
                     tb.rows[i].style.display =  "none";
                 }
                 else
                 {   if(tb.rows[i].id.length == rowid.length+2)
                     {
                         tb.rows[i].style.display =  "block";
                     }
                 }          
             }
         }
    }
    function ch()
    {
        var tb = document.getElementById("tb");
        tb.rows[12].cells[0].children[1].src = "../llmis/images/line_01_2.gif";
    }
    </script>