var activePage = "welkom";

function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true) && 
	    (changeImages.arguments[0] != activePage)) {
		for (var i=1; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

function changeImagesFrame() {
	if (parent.buttons.document.images && (preloadFlag == true) && 
	    (changeImagesFrame.arguments[0] != activePage)) {
		for (var i=1; i<changeImagesFrame.arguments.length; i+=2) {
			parent.buttons.document[changeImagesFrame.arguments[i]].src = changeImagesFrame.arguments[i+1];
		}
	}
}

var preloadFlag = true;
function preloadImages() {
	if (document.images) {
		a = newImage("images/nav_welkom_h.gif");
		b = newImage("images/nav_welkom_s.gif");
		c = newImage("images/nav_bedrijf_h.gif");
		d = newImage("images/nav_bedrijf_s.gif");
		e = newImage("images/nav_activiteiten_h.gif");
		f = newImage("images/nav_activiteiten_s.gif");
		g = newImage("images/nav_wiezijnwij_h.gif");
		h = newImage("images/nav_algemeneinfo_h.gif");
		i = newImage("images/nav_werkzaamheden_h.gif");
		j = newImage("images/nav_hoewerkenwij_h.gif");
		k = newImage("images/nav_ontwerp_h.gif");
		l = newImage("images/nav_calculatie_h.gif");
		m = newImage("images/nav_uitvoering_h.gif");
		n = newImage("images/nav_kwaliteitsbewaking_h.gif");
		o = newImage("images/nav_partners_h.gif");
		p = newImage("images/nav_voordelen_h.gif");
		q = newImage("images/nav_downloads_h.gif");
		r = newImage("images/nav_downloads_s.gif");
		s = newImage("images/tekstkader_tile.gif");
		t = newImage("images/stip_geel1.gif");
		u = newImage("images/stip_geel2.gif");
		v = newImage("images/transpixel.gif");
		preloadFlag = true;
	}
}

function setActivePageFrame(name) { 
	if (document.images) { 
        	changeImagesFrame(name, eval("'menu_" + activePage + "'"), eval("'images/Buttons/" + activePage + ".gif'"));
        	changeImagesFrame(name, eval("'menu_" + name + "'"), eval("'images/Buttons/" + name + "Roll.gif'"));
        	parent.buttons.activePage = name;
	} 
}

function setActivePage(name) { 
	if (document.images) { 
        	changeImages(name, eval("'menu_" + activePage + "'"), eval("'images/Buttons/" + activePage + ".gif'"));
        	changeImages(name, eval("'menu_" + name + "'"), eval("'images/Buttons/" + name + "Roll.gif'"));
        	activePage = name;
	} 
}