jQuery.preloadImages = function()
{
  for(var i = 0; i<arguments.length; i++)
  {
    jQuery("<img>").attr("src", arguments[i]);
  }
};
$.preloadImages("/images/navi_menuoffice_on.png", "/images/navi_master_on.png","/navi_retail_on.png","/images/navi_discover_on.png","/images/navi_highlights_on.png");

$(document).ready(function() { 
$('.navi').hover(function() {
	
	activeSrc = $(this).attr("src");
	activeSrc = activeSrc.replace("_off","_on");
	$(this).attr("src",activeSrc);
		}, function() {
	activeSrc = $(this).attr("src");
	activeSrc = activeSrc.replace("_on","_off");
	$(this).attr("src",activeSrc);
});
});