function change_item(n) {
     var idecka = new Array(1,2,3,4,5,6,7,8);
     if(document.getElementById('item_' + n).style.display=="none") {
	    document.getElementById('item_' + n).style.display="block";
	    for (i=1;i<=idecka.length;i++) {
	     if(n != i) {
	      document.getElementById('item_' + i).style.display="none";
	     }
	    }
     }
    }
    
    function change_class(n) {
     var idecka = new Array(1,2,3,4,5,6,7,8);
     if(document.getElementById('item' + n).className=="normal") {
      for (i=1;i<=idecka.length;i++) {
	     if(n != i) {
	      document.getElementById('item' + i).className="normal next";
	     }
	    }
     }
     else if(document.getElementById('item' + n).className=="normal next") {
      document.getElementById('item1').className="normal";
      for (i=1;i<=idecka.length;i++) {
	     if(n != i && i != 1) {
	      document.getElementById('item' + i).className="normal next";
	     }
	    }
     }
    }
    
    function change_picture(n) {
     var idecka = new Array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30);
     if(document.getElementById('pic_' + n).style.display=="none") {
	    document.getElementById('pic_' + n).style.display="block";
	    for (i=1;i<=idecka.length;i++) {
	     if(n != i) {
	      document.getElementById('pic_' + i).style.display="none";
	     }
	    }
     }
    }