le movi un poquito al codigo que postearon anteriormente para que funcione con IE5 IE5.5 IE6 IE7 y firefox...
ojala les sirva...
Código:
<head>
<script type="text/javascript">
var contLin = 3;
function agregar() {
var tr, td, tabla;
tabla = document.getElementById('tabla');
tr = tabla.insertRow(tabla.rows.length);
td = tr.insertCell(tr.cells.length);
td.innerHTML = "<select id='sel" + contLin + "'>" +
"<option>1" +
"<option>2" +
"<option>3";
td = tr.insertCell(tr.cells.length);
td.innerHTML = "<input type='text' id='t" + contLin + "1' value='t" + contLin + "1'>";
td = tr.insertCell(tr.cells.length);
td.innerHTML = "<input type='text' id='t" + contLin + "2' value='t" + contLin + "2'>";
contLin++;
}
function borrarUltima() {
ultima = document.all.tabla.rows.length - 1;
if(ultima > -1){
document.all.tabla.deleteRow(ultima);
contLin--;
}
}
</script>
</head>
<body>
<form>
<table id="tabla" border="1">
<tr>
<td><select name="sel1" id="sel1">
<option>1</option>
<option>2</option>
<option>3</option>
</select>
</td>
<td><input type="text" id="t11" value="t11"></td>
<td><input type="text" id="t12" value="t12"></td>
</tr>
<tr>
<td><select name="sel2" id="sel2">
<option>1</option>
<option>2</option>
<option>3</option>
</select>
</td>
<td><input type="text" id="t21" value="t21"></td>
<td><input type="text" id="t22" value="t22"></td>
</tr>
</table>
<br>
<input type="button" value="Agregar" onclick="agregar()">
<input type="button" value="Borrar ultima" onclick="borrarUltima()">
</form>
</body>
</html>
saludox