$(document).ready
(
	function()
	{
		//preload images
		$.preloadImages 
		(
			"images/nav/nav_home_o.jpg",
			"images/nav/nav_about_o.jpg",
			"images/nav/nav_visit_o.jpg",
			"images/nav/nav_services_o.jpg",
			"images/nav/nav_resources_o.jpg",
			"images/nav/nav_directions_o.jpg"
		);
		
		//set hover event		
		$("#nav div.nav a").hover
		(
			function()
			{
				var iconName = $(this).find("img").attr("src");
				var origen = iconName.split("x.")[0];
				
				$(this)
				.find("img")
				.attr("src", origen + "o.jpg");
				
			},
			function()
			{
				var iconName = $(this).find("img").attr("src");
				var origen = iconName.split("o.")[0];
				
				$(this)
				.find("img")
				.attr("src", origen + "x.jpg");

			}
		);
	}
);

$.preloadImages = function() {
	for (var i = 0; i<arguments.length; i++) {
		img = new Image();
		img.src = arguments[i];
	}
}