HTML : Question dans un formulaire

<script language="javascript" type="text/javascript">
function redirection() {
	if(document.getElementsByName('btnradio')[0].checked == true)	
		document.location.href='http://fr.yahoo.com/';
	if(document.getElementsByName('btnradio')[1].checked == true)	
		document.location.href='http://www.google.fr';
}
</script>

<input name="btnradio" id="btnradio" type="radio" value="0" />Lien 1
<input name="btnradio" id="btnradio" type="radio" value="1" />Lien 2
<br/>
<input name="btn_envoi" type="button" onclick="redirection()" value="Valider" />

<form action="pagecible.php" method="post">
     <span class="pour_formulaire"> A  pied : </span>
     <label for="oui">Oui</label><input type="radio" name="a_pied" value="oui" id="oui" />
     <label for="non">Non</label><input type="radio" name="a_pied" value="non" id="non" />
     <input type="submit" value="Valider">
</form>

<?php 
if (isset($_POST['a_pied'])) // Si la variable existe
{
     if (($_POST['a_pied']) == "oui" ){ //si il a coché oui
          blabla
     }else{ //si il a coché non
          blabla
     }
}

<input type="submit" value="Valider"/>