Ajout de zone de texte

<tr>
    <td><input tpye="text" name="val"/></td>
    <td><input type="submit" name="ajout"/><td>
</tr>

<button name="Abutton1" onclick="aff_form();">Formulaire</button>
<br/><br/>

<div id="form_1" style="display:none;">
	<form method="post" action="">
		<input type="text" name="val"/>
		<input type="submit" name="ajout" value="Valider"/>
	</form>
</div>

<script type="text/javascript" language="javascript" >

function aff_form()		
{
	document.getElementById('form_1').style.display='block';
}

</script>