Exporting a chart with datetimes to javascript, the values are modified.
This example creates xvalues starting at 0:00 but the xvalues in the javascript side start at 02:00.

procedure TForm1.LocalDatetimeToJavascript;
const fileName='test';
var i: Integer;
    tmp: TDateTime;
begin
  with Chart1.AddSeries(TBarSeries) do
  begin
    XValues.DateTime:=True;
    FillSampleValues;
    Marks.Hide;
    tmp:=Today;

    for i:=0 to Count-1 do
    begin
      XValue[i]:=tmp;
      tmp:=IncHour(tmp,1);
    end;
  end;

  TeeSaveToJavascriptFile(Chart1, fileName+'.html');
  TeeGoToURL(Handle,fileName+'.html');
end;