function PopUp(Site,Breit,Hoch)
{
xsize = Breit-10;
ysize = Hoch+0; 

ScreenWidth = screen.width;
ScreenHeight = screen.height;

xpos = (ScreenWidth/2)-(xsize/2);
ypos = (ScreenHeight/2)-(ysize/2);

 NewWindow=window.open(Site);

 NewWindow.document.close();

 NewWindow.resizeTo(xsize,ysize);
}