function navImOn() {
	imBase = this.id.substring(3);
	im = document.getElementById(this.id);
	im.src = navImsLoc + imBase + "_rollover.gif";
}

function navImOff() {
	imBase = this.id.substring(3);
	im = document.getElementById(this.id);
	im.src = navImsLoc + imBase + ".gif";
}

function initNav() {
	var navContainer = document.getElementById("nav");
    var ims = navContainer.getElementsByTagName("img");
	
	// assign event handlers
	for (var i = 0; i < ims.length; i++) {
        ims[i].onmouseover = navImOn;
        ims[i].onmouseout = navImOff;
	}
	
	// preload rollover images
	var rolloverAreas = new Array("home", "about", "news", "yachts", "itineraries", "corporate", "services", "sitemap", "contact");
	for (var area in rolloverAreas) {
		var rolloverIm = new Image()
		rolloverIm.src = navImsLoc + area + "_rollover.gif";
	}
}

window.onload = initNav;