//AJAX
function ajax(url,idContenu,parametres) {
    var xhr_object = 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;   
 	}   
        
 	xhr_object.open("POST", url, true);   
                 
 	xhr_object.onreadystatechange = function() {   
    		if(xhr_object.readyState == 4) 
    			document.getElementById(idContenu).innerHTML = xhr_object.responseText;
 	} 
          
    xhr_object.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
 	xhr_object.send(parametres);     
}