Hola
greisy
Prueba este ejemplo:
Código PHP:
<html>
<head>
<script type="text/javascript">
var mostrar=0;
function agregar(num) {
tab = document.getElementById('tabla');
if (mostrar != 0)
tab.getElementsByTagName('tr')[mostrar-1].style.display = 'none';
if (num != 0)
tab.getElementsByTagName('tr')[num-1].style.display = '';
mostrar = num;
}
</script>
</head>
<body>
<select onchange="agregar(this.selectedIndex)">
<option value="0">0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<table id="tabla">
<tr style="display:none"><td>fila1</td></tr>
<tr style="display:none"><td>fila2</td></tr>
<tr style="display:none"><td>fila3</td></tr>
</table>
</body>
</html>
Saludos,