function getAppVersion() {
  appname= navigator.appName;
  appversion = navigator.appVersion;
  majorver = appversion.substring(0, 1); 
  if ( (appname == "Netscape") && ( majorver >= 3 ) ) return 1;
  if ( (appname == "Microsoft Internet Explorer") && (majorver >= 4) ) return 1; return 0;}

if (document.images) {
  var img1 = new Image() ; img1.src = "../images/bouton1.gif"
  var img2 = new Image() ; img2.src = "../images/bouton1_on.gif"
  var img3 = new Image() ; img3.src = "../images/bouton2.gif"
  var img4 = new Image() ; img4.src = "../images/bouton2_on.gif"
}
function flip(imgName,imgVar) {
  document[imgName].src = eval(imgVar);
  return true;
}