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) {
		nav_company_over = newImage("img/nav_company-over.gif");
		nav_arma_over = newImage("img/nav_arma-over.gif");
		nav_oborud_over = newImage("img/nav_oborud-over.gif");
		nav_useful_over = newImage("img/nav_useful-over.gif");
		nav_zakaz_over = newImage("img/nav_zakaz-over.gif");
		nav_talk_over = newImage("img/nav_talk-over.gif");
		preloadFlag = true;
	}
}