newwindow=false;
function fenster(url,name,breite,hoehe)
{
if(newwindow&&newwindow.closed==false)
newwindow.close()
var l = 30;
var t = 130;
newwindow = window.open(url,"newwindow","width="+breite+",height=" +hoehe+",left="+l+",top="+t+",scrollbars=0,resizable=0;");
newwindow.focus();
}