js 操作 table

Code
 1  <table border=1 width=400 id=tb>
 2  <tr>
 3  <td>firstLeft</td>
 4  <td>firstRight</td>
 5  </tr>
 6  <tr>
 7  <td>lastLeft</td>
 8  <td>lastRight</td>
 9  </tr>
10  </table>
11 
12 <script language="JavaScript">
13 <!--
14  var n=1;
15 
16  function insertRow() {
17      var row=tb.insertRow(tb.rows.length-1);
18   var cell=row.insertCell(0);
19   cell.innerHTML=n;
20   cell=row.insertCell(1);
21   cell.innerHTML="<a href='javascript://' onclick='removeOne(this)'>remove</a>";
22   n++;
23  }
24 
25  function removeOne(obj) {
26   var _tr=obj.parentNode.parentNode;
27   _tr.parentNode.removeChild(_tr);
28  }
29 
30  function removeAll() {
31   while(tb.rows.length>2){
32    tb.deleteRow( 1 );
33   }
34  }
35 //-->
36 </script>
37  <hr>
38 
39  <input type="button" onclick='insertRow()' value=" insert ">
40   <input type="button" onclick='removeAll()' value=" remove all">
41 

http://www.cnblogs.com/sunjun/archive/2009/08/30/1556600.html