var SearchStr = 'n_'; //take only tags containing this string in the id
var tagToSet = 'div'; //HTML Tag which script is aplying
function domenu(elem)
	{
	resetmenu('topNav');	
	if(document.getElementById(elem) != null){ //Check, if element with this id exists
		document.getElementById(elem).style.display='';
		}	
	}
	
function resetmenu(parent)
	{
	var parentesis = document.getElementById(parent);
	var difsInside = parentesis.getElementsByTagName(tagToSet);
	var legCut = SearchStr.length;
	for(var i = 0; i < difsInside.length; i++)
		{
		var thisid = difsInside[i].id;
		if(thisid.substring(0, legCut) == SearchStr)
			{
			difsInside[i].style.display = 'none';
			}
		}
	}