function recup_category(lettre, cat, univers, root, chemin, id_element)
{
	// Changement de classe
	var elems = document.getElementsByClassName('lettre lettre_active');
	var elems2 = document.getElementsByClassName('lettre toutes_lettres lettre_active');
	
	if (elems.length > 0)
	{
		elems[0].className = "lettre";
		document.getElementById("lettre_"+id_element).className = "lettre lettre_active";
		
	}
	
	if (elems2.length > 0)
	{
		elems2[0].className = "lettre toutes_lettres";
		document.getElementById("lettre_"+id_element).className = "lettre toutes_lettres lettre_active";
		
	}
	
	var xhr_object = null; 
	var filename = root+"serie.php";
	var data =null;
	if(window.XMLHttpRequest) // Firefox 
	   xhr_object = new XMLHttpRequest(); 
	else if(window.ActiveXObject) // Internet Explorer 
	   xhr_object = new ActiveXObject("Microsoft.XMLHTTP"); 
	else { // XMLHttpRequest non supporté par le navigateur 
	   alert("Votre navigateur ne supporte pas les objets XMLHTTPRequest..."); 
	   return;
	}
	
	if(lettre != '')
		data = "lettre="+lettre+"&category="+cat+"&univers="+univers+"&chemin="+chemin;
	
	if(data != null){
		filename += "?"+data;
		data = null;
	}
	
	xhr_object.open("GET", filename, true); 	
	xhr_object.send(null);
	xhr_object.onreadystatechange = function() { 
	   if(xhr_object.readyState == 4) { 
		  document.getElementById('liste').innerHTML = xhr_object.responseText;
	   } 
	}
}