function stopError() { return true; }
window.onerror = stopError;

var win;
//win = 0;
var x = 0;
var y = 0;
var arg  = "";
var win = "";

function popup(url, breite, hoehe, arg){
	if(screen.width > 640)
	{
		x = (screen.availWidth  - breite) / 2;
		y = (screen.availHeight - hoehe) / 2;
	}
	if(arg != '') arg = ',' + arg;
	if(win){ if(win.closed == false){ win.close(); } }
	win = window.open(url,'win','width=' + breite + ',height=' + hoehe + ',top=' + y + ',left=' + x + arg +'');
	if(window.focus){ win.focus(); }
}