function pokazWarstwe(warstwa) {
	var alltags= document.getElementsByTagName("*");
	for (i=0; i<alltags.length; i++){
		if (alltags[i].className=='tresc') 
		alltags[i].style.visibility='hidden';
	}
	document.getElementById(warstwa).style.visibility = 'visible'
}
function changeImg(id, image) {
	document.getElementById(id).src=image;
	window.status='';
}
function showImg(image){
	document.getElementById('screenshot').style.backgroundImage='url('+image+')';
	document.getElementById('screenshot').style.visibility='visible';
}
function hideImg(image){
	document.getElementById('screenshot').style.visibility='hidden';
}