function toggleMenu(layer){

	for(var i=1;i<4;i++){
		document.getElementById('co_nav_' + i).style.borderBottom = '1px solid #CCCCCC';
		document.getElementById('co_nav_' + i).style.backgroundColor = '#FFFFFF';
		document.getElementById('co_' + i).style.display = 'none'; 
	}

	document.getElementById('co_nav_' + layer).style.borderBottom = '0px solid #FFFFFF';
	document.getElementById('co_nav_' + layer).style.borderCollapase = 'collapse';
	document.getElementById('co_nav_' + layer).style.backgroundColor = 'rgb(248,248,248)';

	document.getElementById('co_' + layer).style.display = 'block';
	//style="overflow:scroll;height:400px;"
	if (layer == 2 && screen.height <= 768)
	{
		document.getElementById('co_' + layer).style.overflow = 'scroll';
		document.getElementById('co_' + layer).style.height = '360px';
	} 
}