function Open(page) {
LeftPosition = (screen.width) ? (screen.width-650)/2 : 0;
TopPosition = (screen.height) ? (screen.height-650)/2 : 0;
OpenWin = 
this.open(page,"PopupWindow","toolbar=no,width=650,height=650,left="+LeftPosition+",top="+TopPosition+",directories=no,status=no,scrollbars=yes,resize=no,menubar=no")
}