var logo = document.getElementById('logo');
var increasing = false;
var logoOpacity = 1;
var opacityIncrementAmount = 0.1; // Koska 0 = 0% ja 1 = 100%;
var flashSpeed = 40; //Millisekuntti


setInterval(
	
	function ChangeOpacity() {
		if (logoOpacity < 0) {
			increasing = true;
		}
		
		if (logoOpacity > 1) {
			increasing = false;
		}
		
		if (increasing == false) {
			logoOpacity -= opacityIncrementAmount;
		} else {
			logoOpacity += opacityIncrementAmount;
		}
	
		logo.style.opacity = logoOpacity;
	}
	
,flashSpeed);