onmain=new Image();
onmain.src="/images/nav_home-over.gif";
offmain=new Image();
offmain.src="/images/nav_home.gif";
onabout=new Image();
onabout.src="/images/nav_about-over.gif";
offabout=new Image();
offabout.src="/images/nav_about.gif";
onservices=new Image();
onservices.src="/images/nav_services-over.gif";
offservices=new Image();
offservices.src="/images/nav_services.gif";
onproducts=new Image();
onproducts.src="/images/nav_products-over.gif";
offproducts=new Image();
offproducts.src="/images/nav_products.gif";
oncontact=new Image();
oncontact.src="/images/nav_contact-over.gif";
offcontact=new Image();
offcontact.src="/images/nav_contact.gif";

function rollon(img_name){
onButton=eval("on"+img_name+".src");
document[img_name].src=onButton;
}

function rolloff(){
document.main.src=offmain.src;
document.about.src=offabout.src;
document.services.src=offservices.src;
document.products.src=offproducts.src;
document.contact.src=offcontact.src;

}