var menu_divs = ['droproll1', 'droproll2', 'droproll3'];
var boundary_divs = ['hidedropdown', 'hidedropdown2']//, 'hidedropdown3'];


function toggleLayers(element, action){
	var obj = document.getElementById(element);
	//alert(action);
	if(action=='show'){
		obj.style.visibility = 'visible';
	}else{
		obj.style.visibility = 'hidden';
	}
	
}

function hideMenus(){
	for(i=0; i<menu_divs.length; i++){
		toggleLayers(menu_divs[i], 'hide');
	}
	for(i=0; i<boundary_divs.length; i++){
		toggleLayers(boundary_divs[i], 'hide');
	}
}

function showMenu(menu){
	//(menu);
	for(i=0; i<menu_divs.length; i++){
		if(menu_divs[i]!=menu){
			toggleLayers(menu_divs[i], 'hide');
		}else{
			toggleLayers(menu_divs[i], 'show');
		}
	}
	for(i=0; i<boundary_divs.length; i++){
		toggleLayers(boundary_divs[i], 'show');
	}
}