function popup(content)
{
	var fenster = window.open(content, "Book", "width=1024,height=768,resizable=yes, scrollbars=yes, status=no, menubar=no, toolbar=no");
	w = 1024 + 32;
	h = 768 + 96;
	wleft = (screen.width - w) / 2;
	wtop = (screen.height - h) / 2;
	// IE5 and other old browsers might allow a window that is
	// partially offscreen or wider than the screen. Fix that.
	// (Newer browsers fix this for us, but let's be thorough.)
	if (wleft < 0) {
	  w = screen.width;
	  wleft = 0;
	}
	if (wtop < 0) {
	  h = screen.height;
	  wtop = 0;
	}
	fenster.moveTo(wleft, wtop);
 	fenster.focus();
}