function cascata(id_div) {
	var id_div = document.getElementById(id_div)
	if (id_div.style.display == "none") {
		id_div.style.display="block";
	    //alert(id_div + "block");
    } else {
		id_div.style.display="none";
        //alert(id_div + "none");
	}
}