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;
}
function swtch(num, imgname) {
if (getAppVersion()) {
document[imgname].src = img[num].src;
}
}
imgsrc = new Array();

imgsrc[1] = "images/men_home.gif"; 
imgsrc[2] = "images/men_home_n.gif"; 
imgsrc[3] = "images/men_info.gif"; 
imgsrc[4] = "images/men_info_n.gif";
imgsrc[5] = "images/men_referen.gif"; 
imgsrc[6] = "images/men_referen_n.gif";
imgsrc[7] = "images/men_kontakt.gif"; 
imgsrc[8] = "images/men_kontakt_n.gif"; 

imgsrc[9] = "images/napiste.gif"; 
imgsrc[10] = "images/napiste_n.gif";
imgsrc[11] = "images/hakr.gif"; 
imgsrc[12] = "images/hakr_n.gif";
imgsrc[13] = "images/steko.gif"; 
imgsrc[14] = "images/steko_n.gif"; 
imgsrc[15] = "images/bef.gif"; 
imgsrc[16] = "images/bef_n.gif";
imgsrc[17] = "images/aldo.gif"; 
imgsrc[18] = "images/aldo_n.gif";

if (getAppVersion()) {
img = new Array();
for (i = 0; i < imgsrc.length; i++) {
img[i] = new Image();
img[i].src = imgsrc[i];
}
}