function preloadMenuImages()
{
	var preload_image_array = new Array(12);
	preload_image_array[0]  = '../images/menu_home_on.jpg';
	preload_image_array[1]  = '../images/menu_home_off.jpg';
	preload_image_array[2]  = '../images/menu_services_on.jpg';
	preload_image_array[3]  = '../images/menu_services_off.jpg';
	preload_image_array[4]  = '../images/menu_plist_on.jpg';
	preload_image_array[5]  = '../images/menu_plist_off.jpg';
	preload_image_array[6]  = '../images/menu_news_on.jpg';
	preload_image_array[7]  = '../images/menu_news_off.jpg';
	preload_image_array[8]  = '../images/menu_company_on.jpg';
	preload_image_array[9]  = '../images/menu_company_off.jpg';
	preload_image_array[10] = '../images/menu_contact_on.jpg';
	preload_image_array[11] = '../images/menu_contact_off.jpg';

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