Petit pb en JavaScript

<script type="text/javascript">
					
function test(valeur) {	
     if ((valeur=="a") || (valeur=="b")) {
	 document.getElementById("concerne").style.display = "inline";	
     }					
     else {
	 document.getElementById("concerne").style.display = "none";
       }
       if ((valeur=="a") && (valeur=="e")) {  //la 2 ème condition qui ne marche pas
	 document.getElementById("msg2").style.display = "inline";
	}
	else {
	  document.getElementById("msg2").style.display = "none";
	}	
}	
</script>
<form method="post" name="prem"> <!--action="fichier.php"--> 
 <input name="un_seul_choix" style="width: 26px" type="radio" value="a" onclick="test(this.value);"/>Appartement<p style="width: 156px">
<input name="un_seul_choix" style="width: 26px" type="radio" value="b" onclick="test(this.value);"/>Maison</p><p style="width: 156px">
<input name="un_seul_choix" style="width: 26px" type="radio" value="c" onclick="test(this.value);"/>Local commercial</p><p style="width: 156px">
<input name="un_seul_choix" style="width: 26px" type="radio" value="d" onclick="test(this.value);"/>Parties communes</p>
</form>		
<form method="post" id="concerne" style="display:none;">
<span class="style18"><strong>Il s&#39;agit d'une :</strong></span> <p style="width: 156px"> 
<input name="concerne" style="width: 26px" type="radio" value="e" onclick="test(this.value);"
/>Vente</p><p style="width: 156px"> 
<input name="concerne" style="width: 26px" type="radio" value="f" onclick="test(this.value);"
/>Location Vide</p> <p style="width: 156px"> 
<input name="concerne" style="width: 26px" type="radio" value="g" onclick="test(this.value);"
/>Location meublée</p>
</form>	
<div id="msg2" style="display:none;">
Nombre de pièces :
</div>