<table id="tbl-product">
  <tr>
    <th>#</th>
    <th>product</th>
  </tr>
  <tr>
    <td>1</td>
    <td>cat</td>
  </tr>
</table>
<p><input type="button" name="add-row" id="add-row" value="เพิ่มแถว" /></p>

<script type="text/javascript">
$(document).ready(function(){
 
	$('#add-row').click(function(){
 
		var tr = $('<tr></tr>');
		var td1 = $('<td>#</td>');
		var td2 = $('<td>mouse</td>');
 
		tr.append(td1);
		tr.append(td2);
 
		$('#tbl-product').append(tr);
 
	});
 
 
})
</script>