visible = function(element_id) {
	var div_element;
	div_element = document.getElementById(element_id) ;
	if (div_element.style.display == 'none' || div_element.style.display == '') {
		div_element.style.display = 'block' ;
	} else {
		div_element.style.display = 'none' ;
	}
}

montre_tout = function(nom_element) {
	var les_articles = new Array;
	les_articles = document.getElementsByTagName(nom_element);
	var nbre_articles = les_articles.length;
	for (var i = 0; i < nbre_articles; i++) {
		les_articles[i].style.display = 'block' ;
	}
}

cache_tout = function(nom_element) {
	var les_articles = new Array;
	les_articles = document.getElementsByTagName(nom_element);
	var nbre_articles = les_articles.length;
	for (var i = 0; i < nbre_articles; i++) {
		les_articles[i].style.display = 'none' ;
	}
}