// JavaScript Document
function mapa (URL){
   window.open(URL,"Ubicación","width=600,height=500,scrollbars=YES")
} 
<!--ventana2("proximo.html"); -->
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) {
		home_page_over = newImage("images/home-page-over.jpg");
		about_over = newImage("images/about-over.jpg");
		buying_over = newImage("images/building-over.jpg");
		selling_over = newImage("images/selling-over.jpg");
		renting_over = newImage("images/renting-over.jpg");
		contacts_over = newImage("images/contacts-over.jpg");
		dlaura_over = newImage("images/dlaura-home_onclic.jpg");
		acacias_over = newImage("images/acaciasF-onclic-home.jpg");
		topacios_over = newImage("images/topacios-home_onclic.jpg");
		preloadFlag = true;
	}
}