version= false;
browsername=navigator.appName;
browserver=navigator.appVersion.substring(0,1);
function whichver(){

if (browsername == "Netscape"){
  if (browserver >= 3){
    version=true;
	 }
}	 

if (browsername == "Microsoft Internet Explorer"){
  if (browserver >= 4){
    version=true;
	 }
}

return version;
}

if (true == whichver()){
}

function showPicture(covername){
  if (version == true){
	 window.document['cover'].src=covername;
    }
  }