// stores number of image that is currently shown
	var current_id = 1;
	// stores number of images
	var max_number = 0;
	
	// function that is called when clicking on one of the numbers or "last" or "first"
	function changeView (e)
	{
	    YAHOO.util.Event.preventDefault(e);
		// find out, which image is to be shown
		var number = this.id.split("_");
		number = parseInt(number[1]);
		
		// if it's the same as before, do nothing
		if (number == current_id) { return false; }

		// highlight current number
		// highlight new number, un-highlight current one
		document.getElementById('link_' + current_id).className = document.getElementById('link_' + current_id).className.replace(/selected/, '');
		document.getElementById('link_' + number).className = document.getElementById('link_' + number).className.replace(/selected/, '') + ' selected';

	
		// hide image shown before and show new image
		document.getElementById('img_' + current_id).className = 'hide';
		document.getElementById('img_' + number).className = 'show';
		
		// update window title
		document.title = document.getElementById('img_' + number).getElementsByTagName('img')[0].alt + ' / pi-consult.de';
		current_id = number;
	
		return false;
	}
	
	
	// function called when clicking ">>"
	function oneUp (e)
	{
	    YAHOO.util.Event.preventDefault(e);
		number = current_id + 1;
		// if last image is already shown, do nothing
		if (number > max_number) { return false; }

		// highlight new number, un-highlight current one
		document.getElementById('link_' + current_id).className = document.getElementById('link_' + current_id).className.replace(/selected/, '');
		document.getElementById('link_' + number).className = document.getElementById('link_' + number).className.replace(/selected/, '') + ' selected';
	
		// hide old image, show next one
		document.getElementById('img_' + current_id).className = 'hide';
		document.getElementById('img_' + number).className = 'show';
		
		// update window title
		document.title = document.getElementById('img_' + number).getElementsByTagName('img')[0].alt + ' / pi-consult.de';
		current_id = number;
		
		return false;
	}
	
	
	// function called when clicking "<<"
	function oneDown (e)
	{
	    YAHOO.util.Event.preventDefault(e);
		number = current_id - 1;
		// if first image is already shown, do nothing
		if (number < 1) { return false; }

		// highlight new number, un-highlight current one
		document.getElementById('link_' + current_id).className = document.getElementById('link_' + current_id).className.replace(/selected/, '');
		document.getElementById('link_' + number).className = document.getElementById('link_' + number).className.replace(/selected/, '') + ' selected';
	
		// hide old image, show previous one
		document.getElementById('img_' + current_id).className = 'hide';
		document.getElementById('img_' + number).className = 'show';
		
		// update window title
		document.title = document.getElementById('img_' + number).getElementsByTagName('img')[0].alt + ' / pi-consult.de';
		current_id = number;
		
		return false;
	}

	function setUp ()
	{
		if (document.getElementById('popup_content_img') != null)
		{
			max_number = document.getElementById('popup_content_img').getElementsByTagName('img').length;
			if (max_number < 1) { return; }
			if (max_number == 1) { 
				window.resizeTo((document.getElementById('popup_content_img').getElementsByTagName('img')[0].width + 30), (document.getElementById('popup_content_img').getElementsByTagName('img')[0].height + 70));
				return; 
			}
			var nav_div = document.getElementById('popup_head');
			// check, if navigation links exist
			if (nav_div != null && nav_div != undefined && typeof(nav_div) == "object") 
			{
				// apply events to links
				var navs = nav_div.getElementsByTagName('a');
				for (var i = 0; i < navs.length; i++)
				{
					if (typeof(navs[i]) != "object")
					{
							continue;
					}
					switch (navs[i].id)
					{
						case "up": 
							YAHOO.util.Event.addListener(navs[i],'click',oneUp);
							break;
						case "down": 
							YAHOO.util.Event.addListener(navs[i],'click',oneDown);
							break;
						default:
							YAHOO.util.Event.addListener(navs[i],'click',changeView);
					}
					
				}
			}
			
			// resize
			window.moveTo(0,0);
			window.resizeTo((document.getElementById('popup_content_img').getElementsByTagName('img')[0].width + 120), (document.getElementById('popup_content_img').getElementsByTagName('img')[0].height + 150));
			window.focus();
		}
	}
	YAHOO.util.Event.addListener(window,'load',setUp);