function dropdown(id, vis, changeid, changeclass) {
	
	identity=document.getElementById(id);
	if (vis=='show') {
		if (document.layers)
			document.layers[id].visibility='show';
		else
			document.all[id].style.visibility='visible';
	}
	else if (vis=='hide') {
		if (document.layers)
			document.layers[id].visibility='hide';
		else
			document.all[id].style.visibility='hidden';
	}
	if (changeid != '') {
	change(changeid, changeclass);
	}
	}