function popup(R,N,F) {

var fLeft,fTop;if(screen.width<800){fLeft=0;fTop=0;}else{fLeft=parseInt(screen.availWidth/3);fTop=parseInt(screen.availHeight/3);}
var F2=',top='+fTop+',left='+fLeft+',screenY='+fTop+',screenX='+fLeft;

if(F.search(/(top|left)/)!=-1) { F2='';}

fenster=window.open(R, N,F+F2);

if(fenster.opener==null) {fenster.opener=self;}
return false;
}