jQuery.preloadImages = function()
{
 for(var i = 0; i<arguments.length; i++)
 {
  jQuery("<img>").attr("src", arguments[i]);
 }
};
$.preloadImages("images/navi_about_on.png", "images/navi_about_on.png", "images/navi_careers_on.png", "images/navi_news_on.png", "images/navi_portfolio_on.png");

$(document).ready(function() {
$('.navi').hover(function() {


	var ast=0;
	
	activeSrc = $(this).attr("src");

	if ( activeSrc.indexOf('on.png') < 1) ast=1;

	activeSrc = activeSrc.replace("_off","_on");

	$(this).attr("src",activeSrc);
		}, function() {

	activeSrc = $(this).attr("src");
	activeSrc = activeSrc.replace("_on","_off");
	$(this).attr("src",activeSrc);


});
});