var
Form1: TForm1;
BRUN:BOOL=true;
Tmptime:Tdatetime;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
brun:= not brun ;
repeat
application.ProcessMessages;
if Tmptime<> now then begin
Tmptime:=now;
label1.Caption:=formatdatetime('yy/mm/dd hh:mm:ss.zzz',Tmptime);
end
else sleep(10);
until brun;
end;