Event.observe(window, 'load', page_loaded, false);

function page_loaded(evt) { if ($('panel1')) Event.observe('panel1', 'click', item_clicked, false); }

function item_clicked(evt){
	$$('#gallery li').invoke('removeClassName','active');
	var child = Event.element(evt);
	child.parentNode.addClassName('active');
	medimg = child.src.split('t_')[0] + 'm_' + child.src.split('t_')[1];
	$('pic_img').src = medimg;
	$('pic_p').innerHTML = child.title;
	Event.stop(evt); //avoid another call related to 'parent_node' itself
}

function panel(change) {
	$('panel'+cur_panel).hide();
	cur_panel = cur_panel+change;
	$('panel'+cur_panel).show();
	if(cur_panel==1) { $('prevpanel').hide(); } else { $('prevpanel').show(); }
	if(cur_panel==panels) { $('nextpanel').hide(); } else { $('nextpanel').show(); }
	if(cur_panel>1) {Event.observe('panel'+cur_panel, 'click', item_clicked, false);}
}