function init() {
	/* PRELOAD IMAGES */
	var menuButton1 = new Image();
	menuButton1.src = "./images/wat_is_hover.jpg";
	var menuButton2 = new Image();
	menuButton2.src = "./images/hoe_blijf_hover.jpg";
	var menuButton3 = new Image();
	menuButton3.src = "./images/test_hover.jpg";
	var menuButton4 = new Image();
	menuButton4.src = "./images/cursus_hover.jpg";
	var menuButton5 = new Image();
	menuButton5.src = "./images/forum_hover.jpg";
	var menuButton6 = new Image();
	menuButton6.src = "./images/links_hover.jpg";
}

function toggleMouseOver(img) {
	if (img.src.indexOf("_hover.jpg") == -1)
		img.src = img.src.replace(".jpg", "_hover.jpg");
	else
		img.src = img.src.replace("_hover.jpg", ".jpg");
}

function toggleListStyle(li) {
	if (li.className.indexOf("black") == -1) {
		li.className = "black";
	}
	else {
		li.className = "";
	}
}