var last = 0;

function toggle(num) {
	
	var butt = null;
	var item = null;
	
	butt = document.getElementById('dl-'+num+'a');
	item = document.getElementById('dl-'+num+'b');
	
	if (item.style.display == "" || item.style.display == "none") {
		item.style.display = "block";
		butt.style.backgroundImage = 'url(/images/button/butt_minus.png)';
	} else {
		item.style.display = "none";
		butt.style.backgroundImage = 'url(/images/button/butt_plus.png)';
	}
	
	if (last) {
		
		butt = document.getElementById('dl-'+last+'a');
		item = document.getElementById('dl-'+last+'b');
		
		if (last != num) {
		
			item.style.display = "none";
			butt.style.backgroundImage = 'url(/images/button/butt_plus.png)';
		
		}
	}
	
	last = num;
}