var about_up, about_dn;
var buy_up, buy_dn;
var contact_up, contact_dn;
var prod_up, prod_dn;

var images_loaded = 0;
var browser = navigator.userAgent.substring(0,9);

images_loaded = 0;

if (browser == "Mozilla/3" || browser == "Mozilla/4") {

  about_up = new Image();
  about_up.src = "/images/nav/tan/about_up.gif";
  about_dn = new Image();
  about_dn.src = "/images/nav/tan/about_hit_dn.gif";
  
  buy_up = new Image();
  buy_up.src = "/images/nav/tan/buy_up.gif";
  buy_dn = new Image();
  buy_dn.src = "/images/nav/tan/buy_hit_dn.gif";
  
  contact_up = new Image();
  contact_up.src = "/images/nav/tan/contact_up.gif";
  contact_dn = new Image();
  contact_dn.src = "/images/nav/tan/contact_hit_dn.gif";
  
  prod_up = new Image();
  prod_up.src = "/images/nav/tan/prod_up.gif";
  prod_dn = new Image();
  prod_dn.src = "/images/nav/tan/prod_hit_dn.gif";

  images_loaded = 1;
}

function btnup(btn_name) {
	if ( !images_loaded ) return;
        if (document.images) {
            document[btn_name].src = eval(btn_name + "_up.src");
        }
}

function btndn(btn_name) {
	if ( images_loaded ) {
          if (document.images) {
              document[btn_name].src = eval(btn_name + "_dn.src");
          }
        }
	return true;
}