browserR = (((navigator.appName == "Netscape") && (parseInt(navigator.appVersion) >= 3 )) || ((navigator.appName == "Microsoft Internet Explorer") && (parseInt(navigator.appVersion) >= 4 )))

if (browserR)
{
  nav1_off = new Image;
  nav1_off.src = "images/nav1.gif";
  nav1_on = new Image;
  nav1_on.src = "images/nav1_on.gif";
  
  nav2_off = new Image;
  nav2_off.src = "images/nav2.gif";
  nav2_on = new Image;
  nav2_on.src = "images/nav2_on.gif";
  
  nav3_off = new Image;
  nav3_off.src = "images/nav3.gif";
  nav3_on = new Image;
  nav3_on.src = "images/nav3_on.gif";
  
  nav4_off = new Image;
  nav4_off.src = "images/nav4.gif";
  nav4_on = new Image;
  nav4_on.src = "images/nav4_on.gif";
}