function ukaz(foto,alt,sirka,vyska)
  {
  	var obj = document.getElementById('foto');
  	
  	obj.innerHTML="<p>"+alt+"</p><img src='"+foto+"_.jpg' height='"+vyska+"' width='"+sirka+"' alt='"+alt+"' />";
  	
  	  if (document.documentElement && document.documentElement.scrollTop)
	theTop = document.documentElement.scrollTop;
	else if (document.body)
	theTop = document.body.scrollTop;
	
 obj.style.top = theTop+15+"px";
 obj.style.left = (900-sirka)/2+"px";
  	obj.style.display = 'block';
  	
	document.getElementById('body').style.height = document.documentElement.scrollHeight +"px";
	
  	obj = document.getElementById('overlay');
  	obj.style.height = document.documentElement.scrollHeight +"px";
  	//obj.style.width = document.documentElement.scrollWidth +"px";
	obj.style.display = 'block';
  	}
  
  function zavri()
  {
  	obj = document.getElementById('foto');
	obj.style.display = 'none';
	obj.innerHTML="";
	document.getElementById('overlay').style.display = 'none';
	document.getElementById('body').style.height = "auto";
  }