var NET2 = (navigator.appName == "Netscape" && parseInt(navigator.appVersion) >= 4);
    var invis = (NET2) ? 'hide' : 'hidden';
    var vis = (NET2) ? 'show' : 'visible';
    var im1 = (NET2) ? document.im1 : document.all.im1.style;
    var im2 = (NET2) ? document.im2 : document.all.im2.style;
    var im3 = (NET2) ? document.im3 : document.all.im3.style;
    var im4 = (NET2) ? document.im4 : document.all.im4.style;