var x, y, z;
x = 1024;
y = screen.availHeight - 50;
if(screen.availWidth <= x) {
z = 0;
x = screen.availWidth;
}
else 
z = (screen.availWidth - x)/2;
if(history.length == 0) {
window.resizeTo(x, y);
window.moveTo(z, 10);
}
window.focus(); 

function Ende() {
if(history.length > 0)
history.back();
else
window.close();
}

function OpenWindow(Lnk) {
z = z + 20;
window.open(Lnk,"_blank","width="+x+",height="+y+",top=0,left="+z+",location=yes,toolbar=yes,resizable=yes,scrollbars=yes");
z = z - 20;
}