function rollDown(id) {
		var el = document.getElementById('block' + id);
		var al = document.getElementById('a' + id);
		
		if (el.style.display == 'block') {
			el.style.display = 'none';
			al.style.backgroundImage = "url('i/smallrightarrow.gif')";
		} else {
			el.style.display = 'block';
			al.style.backgroundImage = "url('i/smalldownarrow.gif')";
		}
	}