function rozdzielczosc()
{
	var top_margin = document.getElementById('top');
	var footer_margin = document.getElementById('footer');
	if(screen.height>=800)
	{
		
		top_margin.style.marginTop="30px";
		top_margin.style.marginBottom="30px";
		footer_margin.style.marginTop="30px";
		
    }
}