function hideSection(sec) {
		var el = document.getElementById('s'+sec);
		el.style.display = 'none';
	}
	
	function showSection(sec) {
		for (var i=1;i<=sections;i++) {
			hideSection(i);	
		}
		var el = document.getElementById('s'+sec);
		el.style.display = 'block';
	}