browser_name = navigator.appName;
browser_version = parseFloat(navigator.appVersion); 

if (browser_name == "Netscape" && browser_version >= 3.0) {
  roll = 'true';
}
else if (browser_name == "Microsoft Internet Explorer" && browser_version >= 4.0) {
  roll = 'true';
}
else {
  roll = 'false';
}

function msover(img1,img2) {
  if (roll == 'true') {
    document.images[img1].src = img2;
  }
}

function msout(img1,img2) {
  if (roll == 'true') {
    document.images[img1].src = img2;
  }
}

function MM_preloadImages() {
  if (document.images) {
    var imgFiles = MM_preloadImages.arguments;
    var preloadArray = new Array();
    for (var i=0; i<imgFiles.length; i++) {
      preloadArray[i] = new Image;
      preloadArray[i].src = imgFiles[i];
    }
  }
}

MM_preloadImages('/images/nav_pointer_0.gif');
MM_preloadImages('/images/nav_pointer_1.gif');