$('#myTextField').keyup(function() {
   $('#myButton').attr('disabled', !$('#myTextField').val());
});

function timetolog(reqdate: TdateTime): string;
var
  Y, m, d, hh, mm, ss, ms: WORD;
  newy, newm, newd, newhh, newmm, newss: string;
begin
  DecodeDate(reqdate, Y, m, d);
  DecodeTime(reqdate, hh, mm, ss, ms);
  newy := inttostr(Y);
  newm := inttostr(m);
  newd := inttostr(d);
  newhh := inttostr(hh);
  newmm := inttostr(mm);
  newss := inttostr(ss);
  if length(newm) = 1 then
    newm := '0' + newm;
  if length(newd) = 1 then
    newd := '0' + newd;
  if length(newhh) = 1 then
    newhh := '0' + newhh;
  if length(newmm) = 1 then
    newmm := '0' + newmm;
  if length(newss) = 1 then
    newss := '0' + newss;
  Result := '[' + newd + '.' + newm + '.' + newy + ' ' + newhh + ':' + newmm +
    ':' + newss + '] ';
end;

procedure AddLog(ARichEdit: TRichEdit; AText: string);
var
  Count: Integer;
begin
  AText := timetolog(now) + AText;
  Count := pos(']', AText) + 1;
  if pos('ERROR', AText) > 0 then
  begin
    ARichEdit.Lines.Add(AText);
    ARichEdit.SelStart := length(ARichEdit.Text);
    ARichEdit.SelStart := ARichEdit.SelStart - length(AText) - 1;
    ARichEdit.SelLength := Count;
    ARichEdit.SelAttributes.Style := [fsbold];
    ARichEdit.SelAttributes.Color := rgb(180, 10, 10);
    ARichEdit.SelStart := ARichEdit.SelStart + Count;
    ARichEdit.SelLength := length(AText) - Count;
    ARichEdit.SelAttributes.Style := [];
    ARichEdit.SelAttributes.Color := rgb(180, 10, 10);
    ARichEdit.SelLength := 0;
  end
  else
  begin
    ARichEdit.Lines.Add(AText);
    ARichEdit.SelStart := length(ARichEdit.Text);
    ARichEdit.SelStart := ARichEdit.SelStart - length(AText) - 1;
    ARichEdit.SelLength := Count;
    ARichEdit.SelAttributes.Style := [fsbold];
    ARichEdit.SelStart := ARichEdit.SelStart + Count;
    ARichEdit.SelLength := length(AText) - Count;
    ARichEdit.SelAttributes.Style := [];
    ARichEdit.SelLength := 0;
  end;
  SendMessage(ARichEdit.Handle, EM_SCROLL, SB_LINEDOWN, 0);
  try
    ARichEdit.SetFocus;
    ARichEdit.SelStart := ARichEdit.GetTextLen;
    ARichEdit.Perform(EM_SCROLLCARET, 0, 0);
    CreateCaret(ARichEdit.handle, 0, 0, 0);
  except
    //
  end;
  application.ProcessMessages;
end;


procedure TForm1.btn1Click(Sender: TObject);
begin
  AddLog(Form1.RichEdit1, 'ERROR: Something Wrong!'); //Error Message
  AddLog(Form1.RichEdit1, 'Some text here'); //Regular Message
end;

$("#error_box").fadeIn(500).delay(3000).fadeOut(500);