if (document.images) {

 	resource_guide_signup_off = new Image();
   	resource_guide_signup_off.src = "images/resource_guide_signup_off.gif";
   	resource_guide_signup_on = new Image();
    resource_guide_signup_on.src = "images/resource_guide_signup_on.gif";   

 	resource_newsletter_off = new Image();
   	resource_newsletter_off.src = "images/resource_newsletter_off.gif";
   	resource_newsletter_on = new Image();
    resource_newsletter_on.src = "images/resource_newsletter_on.gif";  
    
    resource_quiz_off = new Image();
   	resource_quiz_off.src = "images/resource_quiz_off.gif";
   	resource_quiz_on = new Image();
    resource_quiz_on.src = "images/resource_quiz_on.gif";  
     
    contact_off = new Image();
   	contact_off.src = "images/nav_contact-us_off.gif";
   	contact_on = new Image();
    contact_on.src = "images/nav_contact-us_on.gif";   
    
 }
 
 
 function imgOn(imgName) {
	if (document.images) {	
		document[imgName].src = eval(imgName + "_on.src")
	}
}

function imgOff(imgName) {
	if (document.images) {
   		document[imgName].src = eval(imgName + "_off.src")
   	}
}