select选择事件问题

<HTML> 
<HEAD> 
<TITLE> New Document </TITLE> 
</HEAD> 
    <script language="JavaScript">     
     function addTktTypeRow(){             
             var tbl = document.getElementById('tktTypeGrpTable'); 
             var rowsLen = tbl.rows.length 
             var tr=tbl.insertRow(rowsLen); 
             var cs = new Array(); 
             var forSize = 2; 
             for(var i=0;i < forSize; i++){ 
                cs[i] = tr.insertCell(); 
             } 
             var i=0;                           
        cs[i++].innerHTML ='<select onchange="parentNode.nextSibling.lastChild.value=options[selectedIndex].text"><option>清选择</option><option value="BBC">A</option><option value="DHL">B</option><option value="FBI">C</option><select>';         
        cs[i++].innerHTML ='<input type="text" name="tktTypeDesc" readOnly="true">'; 
        } 
        </script> 
<BODY> 
<input type="button" name="button" onclick="addTktTypeRow()" value="add"> 
 <table id="tktTypeGrpTable" width=100% cellpadding="0" cellspacing="3"> 
  <thead> 
        <tr bgcolor="#FFFFFF">                           
            <td class="tableHeader">Code</td> 
            <td class="tableHeader">Description</td> 
        </tr> 
    </thead> 
 </table> 
</BODY> 
</HTML>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]

<HTML> 
<HEAD> 
<TITLE> New Document </TITLE> 
</HEAD> 
    <script language="JavaScript">     
     function addTktTypeRow(){             
             var tbl = document.getElementById('tktTypeGrpTable'); 
             var rowsLen = tbl.rows.length 
             var tr=tbl.insertRow(rowsLen); 
             var cs = new Array(); 
             var forSize = 2; 
             for(var i=0;i < forSize; i++){ 
                cs[i] = tr.insertCell(); 
             } 
             var i=0;                           
        cs[i++].innerHTML ='<select onchange="parentNode.nextSibling.lastChild.value=options[selectedIndex].getAttribute(\'aaa\')"><option>清选择</option><option aaa="BBC">A</option><option aaa="DHL">B</option><option aaa="FBI">C</option><select>';         
        cs[i++].innerHTML ='<input type="text" name="tktTypeDesc" readOnly="true">'; 
        } 
        </script> 
<BODY> 
<input type="button" name="button" onclick="addTktTypeRow()" value="add"> 
 <table id="tktTypeGrpTable" width=100% cellpadding="0" cellspacing="3"> 
  <thead> 
        <tr bgcolor="#FFFFFF">                           
            <td class="tableHeader">Code</td> 
            <td class="tableHeader">Description</td> 
        </tr> 
    </thead> 
 </table> 
</BODY> 
</HTML>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]