function centerpopup(w,h,p,s,name){
var left = (screen.availWidth/2) - (w/2);
var top = (screen.availHeight/2) - (h/2);
window.open(p,name,'width='+w+',height='+h+', scrollbars='+s+',status=0, left='+left+', top='+top)
}
window.name="hauptfenster";