var images = new Array('imgContact', 'imgOrganisatie', 'imgScholen'); 
var speed = 20;
var interval = 10;
var opacityminimum = 50;  // 0..100

function hide(im1, im2)
 {
    i1 = document.getElementById(images[im1]);
    i2 = document.getElementById(images[im2]);

    i1.style.zIndex = 1;
    i2.style.zIndex = 1;

    if(i1)
	    fadeOut(i1.id,100);
	if(i2)
	    fadeOut(i2.id,100);
    
 }

function show(im1, im2)
 {
    document.getElementById(images[0]).style.zIndex = 2;
    document.getElementById(images[1]).style.zIndex = 2;
    document.getElementById(images[2]).style.zIndex = 1;
    
    i1 = document.getElementById(images[im1]);
    i2 = document.getElementById(images[im2]);

    if(i1)
	    fadeIn(i1.id,0);
	if(i2)
	    fadeIn(i2.id,0);
 }


function fadeOut(objId,opacity) {
	if (document.getElementById) {
		obj = document.getElementById(objId);
		if (opacity >= opacityminimum) {
			setOpacity(obj, opacity);
			opacity -= speed;
			window.setTimeout("fadeOut('"+objId+"',"+opacity+")", interval);
		}
	}
}

function fadeIn(objId,opacity) {
	if (document.getElementById) {
		obj = document.getElementById(objId);
		if (opacity <= 100) {
			setOpacity(obj, opacity);
			opacity += speed;
			window.setTimeout("fadeIn('"+objId+"',"+opacity+")", interval);
		}
	}
}


function setOpacity(obj, opacity) {
	opacity = (opacity == 100)?99.999:opacity;
	// IE/Win
	obj.style.filter = "alpha(opacity:"+opacity+")";
	// Safari<1.2, Konqueror
	obj.style.KHTMLOpacity = opacity/100;
	// Older Mozilla and Firefox
	obj.style.MozOpacity = opacity/100;
	// Safari 1.2, newer Firefox and Mozilla, CSS3
	obj.style.opacity = opacity/100;
}