function affiche_cache_div(id_div) {
	if ( document.getElementById(id_div).style.visibility == 'visible' && document.getElementById(id_div).style.display == 'block' ) {
		document.getElementById(id_div).style.visibility = 'hidden';
		document.getElementById(id_div).style.display = 'none';
	} else {
		document.getElementById(id_div).style.visibility = 'visible';
		document.getElementById(id_div).style.display = 'block';
	}
}