function afficher_reponse(id_question,nb_question) {
	var element = Array();
	
	for(i=0;i<nb_question;i++) {
		element[i] = document.getElementById("question_" + i);
		if(element[i]) {
			element[i].style.display = "none";
		}
	}
	
	if(element[id_question]) {
		element[id_question].style.display = "block";
	}
}