// preload images in title bar, so they show faster
	function preloadImages()
	{
		var imgs;
		var img;
		var n;
		imgs = new Array("welkom.gif", "testlogo.gif", "tipslogo", "uitleglogo.gif", "nieuwsbrieflogo.gif", "co2linkslogo.gif", "faqlogo.gif", "colofonlogo.gif");
		// add path
		for (n in imgs)
		{
			imgs[n] = "images/" + imgs[n];
			// preload
			img = new Image();
			img.src = imgs[n];
		}
	}
	
	// put images and text in the logo bar
	function fillLogoPlaceholder (id) {
		var content = "test";
		switch (id) {
			case "home" :
				content = "<span style='color:blue;font:bold 14px arial'>werk in uitvoering</span>&nbsp;&nbsp;&nbsp;<img src=\"images/welkom.gif\" width=\"400\" height=\"40\" border=\"0\" alt=\"Welkom bij Carbon Credits!\">";
				break;
			case "test" :
				content = "<img src=\"images/testlogo.gif\" width=\"300\" height=\"30\" border=\"0\" alt=\"Carbon Credits, test jezelf!\"><br><font size=\"1\">Klik op elk moment op 'toon grafiek' om uw grafiek te zien. </font>&nbsp;";
				break;
			case "tips" :
				content = "<img src=\"images/tipslogo.gif\" width=\"350\" height=\"30\" border=\"0\" alt=\"Een kleine moeite, een groot verschil!\"><br><font size=\"1\">";
				break;
			case "uitleg" :
				content = "<img src=\"images/uitleglogo.gif\" width=\"200\" height=\"30\" border=\"0\" alt=\"www.carboncredits.info\">&nbsp;";
				break;
			case "nieuwsbrief" :
				content = "<img src=\"images/nieuwsbrieflogo.gif\" width=\"162\" height=\"30\" border=\"0\" alt=\"Blijf op de hoogte\">&nbsp;&nbsp;&nbsp;&nbsp;";
				break;
			case "links" :
				content = "<img src=\"images/co2linkslogo.gif\" width=\"300\" height=\"30\" border=\"0\" alt=\"CO 2 Links\">";
				break;
			case "faq" :
				content = "	<img src=\"images/faqlogo.gif\" width=\"300\" height=\"30\" border=\"0\" alt=\"Veelgestelde vragen\">";
				break;
			case "colofon" :
				content = "<img src=\"images/colofonlogo.gif\" width=\"200\" height=\"30\" border=\"0\" alt=\"Wie zit hierachter?\">&nbsp;";
				break;
			default :
				content = "&nbsp;";
				break;
		}
		document.getElementById("logoplaceholder").innerHTML = content;
	}

	// see if a person has 1024x768, else show fullscreen
	function testResolution() {
		if ((screen.width == 640) && (screen.height == 480)) 
			alert("Waarschuwing: uw resolutie is te laag voor het\ngoed kunnen bekijken van deze website");
		else if ((screen.width == 800) && (screen.height == 600))
			alert(	"Waarschuwing: uw resolutie is niet ideaal voor het" +
					"\ngoed kunnen bekijken van deze website" +
					"\nU kunt het beste uw scherm op full-screen zetten." +
					"\n(Druk op F11 in Internet Explorer)");
	}

	// initialize the interface
	function initHomepage()
	{
		preloadImages();
		fillLogoPlaceholder("home");
		testResolution();
	}