<script> 
 var i=2 
//allCount=1 
function   insRow()   //һ 
{ 
        x=ttb98.insertRow(ttb98.rows.length); 
      var  num=document.getElementById('ttb98').value;
        x.ln=i; 
        h2=x.insertCell(0);
        h1=x.insertCell(1); 
        
        h2.innerHTML="";
        //c1.ln=allCount; 
        h1.innerHTML= ""+(i-1)+"&nbsp;<input   type=button   value= 'ɾ '   ln= "   +   i   +   "   onclick= 'javascript:delRow(); '> " 

        i=i+1;  //ܼƶ 
       // frm.count.value   =   i; 

} 

function   delRow()   //ɾһ 
{ 
        line   =   parseInt(event.srcElement.ln,10); 

        if   (line> 0){ 
                for   (j=1;j <ttb98.rows.length;j++) {

      if   (ttb98.rows[j].ln==line)   //
                        { 
                                ttb98.deleteRow(j); 
              i--; 
           //   frm.count.value   =     i; 
                        } 
                        }
                        }
} 
</script>
<table id="ttb98" border="1">
    <tbody>
        <tr>
            <td width="100"><input type="button" value="add" onclick= "insRow() " /></td>
        </tr>
    </tbody>
</table>