//Button / Panel Arrays
var panel_opacity = 0,
	panel_interval_id = 0,
	current_panel, previous_panel, current_panel_img, previous_panel_img;

function show_panel(idx)
{
	//ignore if user is re-clicking active ID
	if (idx == current_panel_idx) {return false;}
	
	//Destroy any existing timer
	clearInterval(panel_interval_id);
	
	//swap panels
	previous_panel_idx = current_panel_idx;	current_panel_idx = idx;
	
	//switch buttons
	document.getElementById('loc_button_' + previous_panel_idx).className = 'pf_button';
	document.getElementById('loc_button_' + current_panel_idx).className = 'pf_button_set';
	
	//Get current and previous panels / images
	current_panel = document.getElementById('loc_panel_' + current_panel_idx);
	previous_panel = document.getElementById('loc_panel_' + previous_panel_idx);
	current_panel_img = document.getElementById('loc_panel_img_' + current_panel_idx);
	previous_panel_img = document.getElementById('loc_panel_img_' + previous_panel_idx);

	//Swap info blocks / crossfade images
	previous_panel_img.style.zIndex = 0;

	set_opacity(current_panel_img,0);
	current_panel_img.style.zIndex = 1;
	previous_panel.style.display = 'none';
	current_panel.style.display = 'block';
	current_panel_img.style.display = 'block';
	panel_interval_id = setInterval ( 'fadein_panel()', 50 );
	
	return false;
}

function fadein_panel()
{
	if(panel_opacity >= 0.95)
	{
		panel_opacity = 0;
		clearInterval(panel_interval_id);
		set_opacity(current_panel_img,1);
		previous_panel_img.style.display = 'none';
	}
	else
	{
		panel_opacity += 0.05;
		set_opacity(current_panel_img, panel_opacity);
	}
}

function set_opacity(element,opacity)
{
	element.style.opacity = opacity;							//CSS Correct
	element.style.filter = 'alpha(opacity:'+(opacity*100)+')'; //IE	hack
}