function popupBild(weite,hoehe,url,bildname)
{
	centerleft	= (screen.availWidth/2)-(weite/2);
	centertop	= (screen.availHeight/2)-(hoehe/2);
    win	= window.open(url,bildname,"width="+weite+",height="+hoehe+",left="+centerleft+",top="+centertop+"");
	win.focus();
}