function toggleNav(nav_img, nav_sec) {
		var e = document.getElementById(nav_sec).style;
		if (nav_img.className=='closed') { 
			nav_img.className='';
			e.height = 'auto';
			e.overflow = '';
		} else {
			nav_img.className='closed';
			e.overflow = 'hidden';
			e.height = '26px';
		}	
}