function Stretch(document) {
	
	var aktual_size = document.getElementById("main-obal").clientHeight;
	var y = document.documentElement.clientHeight;
	var otisk = navigator.userAgent;
	
	if(otisk.indexOf("Opera") != -1)
	{ 
		y = window.innerHeight;
	}

	if(aktual_size <= y)
	{
		document.getElementById("main-obal").style.height = y +"px";
	}
		
	return;
}