function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		nav_nowenroll_on = newImage("/img/nav_nowenroll_on.gif");
		nav_nowenroll_off = newImage("/img/nav_nowenroll_off.gif");
		nav_doi_on = newImage("/img/nav_doi_on.gif");
		nav_doi_off = newImage("/img/nav_doi_off.gif");
		nav_contact_on = newImage("/img/nav_contact_on.gif");
		nav_contact_off = newImage("/img/nav_contact_off.gif");
		home_tab_patient_off = newImage("/img/home_tab_patient_off.jpg");
		home_tab_patient_on = newImage("/img/home_tab_patient_on.jpg");
		home_tab_doctor_on = newImage("/img/home_tab_doctor_on.jpg");
		home_tab_doctor_off = newImage("/img/home_tab_doctor_off.jpg");
		contact_falcon_off = newImage("/img/callouts/contact_falcon_off.jpg");
		contact_falcon_on = newImage("/img/callouts/contact_falcon_on.jpg");
		find_a_trial_site_on = newImage("/img/callouts/find_a_trial_site_on.jpg");
		find_a_trial_site_off = newImage("/img/callouts/find_a_trial_site_off.jpg");
		preloadFlag = true;
	}
}