function ukaz(obj, nr_obj) {
var foo = document.getElementById(obj); // get the "foo" object
	var i;
	for (i=1; i<=nr_obj;i++)	{
		if ('sub_' + i != obj){
			document.getElementById('sub_' + i).style.display="none";
			document.getElementById('ul_' + i).setAttribute("class", "nobg");
		}else{
			if (foo.style.display == 'block'){
				foo.style.display="none";
				document.getElementById('ul_' + i).setAttribute("class", "nobg");
			}else{
				foo.style.display="block";
				document.getElementById('ul_' + i).setAttribute("class", "bg");
			}
		}
	}
}