var preloaded = [];

preloaded[1]=[loadImage("images/menu_dienstverlening.gif"), loadImage("images/menu_dienstverlening.gif")];
preloaded[2]=[loadImage("images/menu_advies.gif"), loadImage("images/menu_advies.gif")];
preloaded[3]=[loadImage("images/menu_algemeneinformatie.gif"), loadImage("images/menu_algemeneinformatie.gif")];
preloaded[4]=[loadImage("images/menu_contact.gif"), loadImage("images/menu_contact.gif")];

function init() {
if (mtDropDown.isSupported()) {
mtDropDown.initialize();

menu1.onactivate = function() { swapImage("button1", preloaded[1][1].src) };
menu1.ondeactivate = function() { swapImage("button1", preloaded[1][0].src) };

menu2.onactivate = function() { swapImage("button2", preloaded[2][1].src) };
menu2.ondeactivate = function() { swapImage("button2", preloaded[2][0].src) };

menu3.onactivate = function() { swapImage("button3", preloaded[3][1].src) };
menu3.ondeactivate = function() { swapImage("button3", preloaded[3][0].src) };

menu4.onactivate = function() { swapImage("button4", preloaded[4][1].src) };
menu4.ondeactivate = function() { swapImage("button4", preloaded[4][0].src) };
}
}

// preloader
function loadImage(sFilename) {
	var img = new Image();
	//img.src ="/nom du répertoire/" + sFilename;
	img.src =sFilename;
	return img;
}

// swapper l'image
function swapImage(imgName, sFilename) {
	document.images[imgName].src = sFilename;
}