if(window.addEventListener){ // Mozilla, Netscape, Firefox
		window.addEventListener('load', preloadImages, false);
} else { // IE
		window.attachEvent('onload', preloadImages);
}

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

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

var preloadFlag = false;

function preloadImages() {
	if (document.images) {
		europa_over = newImage("/immagini/mappe/sales_W_europa.jpg");
		africa_over = newImage("/immagini/mappe/sales_W_africa.jpg");
		asia_over = newImage("/immagini/mappe/sales_W_asia.jpg");
		oceania_over = newImage("/immagini/mappe/sales_W_oceania.jpg");
		america_over = newImage("/immagini/mappe/sales_W_america.jpg");
		preloadFlag = true;
	}
}

preloadImages();