function preload(imgObj,imgSrc) {
	if (document.images) {
		eval(imgObj+' = new Image()')
		eval(imgObj+'.src = "'+imgSrc+'"')
	}
}

function changeImage(layer,imgName,imgObj) {
	if (document.images) {
		if (document.layers && layer!=null) eval('document.'+layer+'.document.images["'+imgName+'"].src = '+imgObj+'.src')
		else document.images[imgName].src = eval(imgObj+".src")
	}
}

// hoofdmenu plaatjes
preload('homeoff','/images/knop_home.gif');
preload('homeon','/images/knop_home_ro.gif');

preload('toursoff','/images/knop_tours.gif');
preload('tourson','/images/knop_tours_ro.gif');

preload('toursphotosoff','/images/knop_toursphotos.gif');
preload('toursphotoson','/images/knop_toursphotos_ro.gif');

preload('hostelsoff','/images/knop_hostels.gif');
preload('hostelson','/images/knop_hostels_ro.gif');

preload('faqoff','/images/knop_faq.gif');
preload('faqon','/images/knop_faq_ro.gif');

preload('testimonialsoff','/images/knop_testimonials.gif');
preload('testimonialson','/images/knop_testimonials_ro.gif');

preload('quizoff','/images/knop_quiz.gif');
preload('quizon','/images/knop_quiz_ro.gif');

preload('guestbookoff','/images/knop_guestbook.gif');
preload('guestbookon','/images/knop_guestbook_ro.gif');

preload('linksoff','/images/knop_links.gif');
preload('linkson','/images/knop_links_ro.gif');

preload('about_usoff','/images/knop_about_us.gif');
preload('about_uson','/images/knop_about_us_ro.gif');

preload('loginoff','/images/knop_login.gif');
preload('loginon','/images/knop_login_ro.gif');

preload('logoutoff','/images/knop_logout.gif');
preload('logouton','/images/knop_logout_ro.gif');

preload('mailaddressesoff','/images/knop_mailaddresses.gif');
preload('mailaddresseson','/images/knop_mailaddresses_ro.gif');