if (parseInt(navigator.appVersion.substring(0,1))>=3) { 

nav1_on = new Image()
nav1_off = new Image();
nav2_on = new Image();
nav2_off = new Image();
nav3_on = new Image();
nav3_off = new Image();
nav4_on = new Image();
nav4_off = new Image();
nav5_on = new Image();
nav5_off = new Image();
nav1_off.src = 'http://64.124.77.203/ff5/tour/free/t1/nav1_off.gif';
nav1_on.src = 'http://64.124.77.203/ff5/tour/free/t1/nav1_on.gif';
nav2_off.src = 'http://64.124.77.203/ff5/tour/free/t1/nav2_off.gif';
nav2_on.src = 'http://64.124.77.203/ff5/tour/free/t1/nav2_on.gif';
nav3_off.src = 'http://64.124.77.203/ff5/tour/free/t1/nav3_off.gif';
nav3_on.src = 'http://64.124.77.203/ff5/tour/free/t1/nav3_on.gif';
nav4_off.src = 'http://64.124.77.203/ff5/tour/free/t1/nav4_off.gif';
nav4_on.src = 'http://64.124.77.203/ff5/tour/free/t1/nav4_on.gif';
nav5_off.src = 'http://64.124.77.203/ff5/tour/free/t1/nav5_off.gif';
nav5_on.src = 'http://64.124.77.203/ff5/tour/free/t1/nav5_on.gif';



}
function on(image) {
  if (parseInt(navigator.appVersion.substring(0,1))>=3) { // 3.0 or greater.
      imagesrc = eval(image + '_on.src');
      document[image].src = imagesrc;
  }
}
function off(image) {
  if (parseInt(navigator.appVersion.substring(0,1))>=3) { // 3.0 or greater.
      imagesrc = eval(image + "_off.src");
      document[image].src = imagesrc;
 }
}