function post(){
			obj=document.getElementById('message');
			data=obj.value;
			request = new XMLHttpRequest;
			request.open('POST', 'index.php', true);
			
			request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
			request.send("message="+data+"&pseudo=roger");// ici on met name=valeur
			obj.value='';
		}