function WindowZentriert(mypage,myname,w,h,scroll)
{
var win = null;
LeftPosition = (screen.width) ? (screen.width-w)/2 : 0;
TopPosition = (screen.height) ? (screen.height-h)/2 : 0; 
settings = 'height='+h+',width='+w+',top='+TopPosition+',left='+LeftPosition+',scrollbars='+scroll+',resizable=yes,toolbar=0,location=0,directories=0,status=0,menuBar=0' 
win = window.open(mypage,myname,settings)
if(win.window.focus){win.window.focus();} 
}