insertRow,insertCell

<script>
function addRow() {
  var oRow = dyntbl1.insertRow();
  oRow.onmouseover=function(){dyntbl1.clickedRowIndex=this.rowIndex};
  var oCell1 = oRow.insertCell();
  var oCell2 = oRow.insertCell();
  var oCell3 = oRow.insertCell();
  var oCell4 = oRow.insertCell();
  oCell1.innerHTML = "<input type=text name=itemcode>";
  oCell2.innerHTML = "<input type=text name=itemname>";
  oCell3.innerHTML = "<input type=text name=itemnum>";
  oCell4.innerHTML = "<input type=button value=\" X \" onClick=\"delRow()\">";
  document.recalc();
}
function delRow() {
  dyntbl1.deleteRow(dyntbl1.clickedRowIndex);
}

function fixscreen() {
  var buffer = document.all.item(0).outerHTML;
  document.open("text/html", "replace");
  document.write(buffer);
  document.close();
}

function addCol() {
  var vCell,tmp;
  for (var i=0; i<dyntbl1.rows.length; i++) {
    tmp=dyntbl1.rows[i].cells[dyntbl1.rows[i].cells.length-1].cloneNode(true);
    dyntbl1.rows[i].deleteCell();
    vCell=dyntbl1.rows[i].insertCell();
    vCell.innerHTML=i==0?"<input type=button value=' X ' onclick='delCol(parentNode.cellIndex)'>":"&nbsp;";
    vCell=dyntbl1.rows[i].insertCell();
    vCell.innerHTML=tmp.innerHTML;
  }
}
function delCol(idx) {
  for (var i=0; i<dyntbl1.rows.length; i++) {
    dyntbl1.rows[i].cells[idx].removeNode();
  }
}

</script>
 <form>
<input type=button value="화면고정" onClick="fixscreen()">
<table id=dyntbl1 border=1>
  <tr>
    <th>품목코드</th>
    <th>품목명</th>
    <th>갯수</th>
    <th><input type=button value=" + " onClick="addRow()"><input type=button value=" + " onClick="addCol()"></th>
  </tr>
  <tr onMouseOver="dyntbl1.clickedRowIndex=this.rowIndex">
    <td><input type=text name=itemcode></td>
    <td><input type=text name=itemname></td>
    <td><input type=text name=itemnum></td>
    <td><input type=button name=dyntbl1_delRow value=" X " onClick="delRow()"></td>
  </tr>
  <tr onMouseOver="dyntbl1.clickedRowIndex=this.rowIndex">
    <td><input type=text name=itemcode></td>
    <td><input type=text name=itemname></td>
    <td><input type=text name=itemnum></td>
    <td><input type=button name=dyntbl1_delRow value=" X " onClick="delRow()"></td>
  </tr>
</table>
</form>

</body>
</html>