browserName = navigator.appName;
browserVer = parseInt(navigator.appVersion);
if ((browserName == "Netscape" && browserVer >="3" ) || (browserName == "Microsoft Internet Explorer" && browserVer >="4" ) ) 
  version = "nobug";
else 
  version = "bug";

if (version == "nobug") {
  // preload universal images:
  root = "http://www.xs4all.nl/~sjaak/vwgvl";
  arrow_left_on = new Image(15,15);
  arrow_left_on.src = root + "/images/arrow_left_on.gif";
  arrow_left_off = new Image(15,15);
  arrow_left_off.src = root + "/images/arrow_left.gif";
  arrow_right_on = new Image(15,15);
  arrow_right_on.src = root + "/images/arrow_right_on.gif";
  arrow_right_off = new Image(15,15);
  arrow_right_off.src = root + "/images/arrow_right.gif";
  arrow_stop_on = new Image(15,15);
  arrow_stop_on.src = root + "/images/arrow_stop_on.gif";
  arrow_stop_off = new Image(15,15);
  arrow_stop_off.src = root + "/images/arrow_stop.gif";
  arrow_stop2_on = new Image(15,15);
  arrow_stop2_on.src = root + "/images/arrow_stop2_on.gif";
  arrow_stop2_off = new Image(15,15);
  arrow_stop2_off.src = root + "/images/arrow_stop2.gif";
  arrow_home_on = new Image(15,15);
  arrow_home_on.src = root + "/images/arrow_home_on.gif";
  arrow_home_off = new Image(15,15);
  arrow_home_off.src = root + "/images/arrow_home.gif";
}

function img_on(imgName) {
  if (version == "nobug") {
	imgOn = eval(imgName + "_on.src");
	document [imgName].src = imgOn;
  }
}

function img_off(imgName) {
  if (version == "nobug") {
	imgOff = eval(imgName + "_off.src");
	document [imgName].src = imgOff;
  }
}

function img_on_bot(imgName) {
  if (version == "nobug") {
	imgOn = eval(imgName + "_on.src");
	document [imgName + "_bot"].src = imgOn;
  }
}

function img_off_bot(imgName) {
  if (version == "nobug") {
	imgOff = eval(imgName + "_off.src");
	document [imgName + "_bot"].src = imgOff;
  }
}