function popup(nom_de_la_page){
	window.open (nom_de_la_page, "Glowria");
}

function hidden(elem){
    var el = document.getElementById(elem);

    if (el != null) {
        el.style.visibility = "hidden";
    }
}

function visible(elem){
    var el = document.getElementById(elem);

    if (el != null) {
        el.style.visibility = "visible";
    }
}