var browser = navigator.appName
var verze = parseInt(navigator.appVersion)
if ((browser == "Microsoft Internet Explorer" & verze >= 4) | (browser == "Netscape" & verze >= 4))
{ 
sirka = screen.width
vyska = screen.height
asirka = screen.availWidth
avyska = screen.availHeight
color = screen.colorDepth
}
else {sirka=1024};

var x;
x = (sirka - 1024)/2 + 501;
if (sirka < 1024) { x = 501};
document.write("<div style='position: absolute; top: 10px; left: "+ x +"px'>");