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if
Programm sucht 'hallo' := True
then
tu das und das					

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{....}

  private
    procedure SearchAndHighlightText(aText: string);
    
{....}

procedure TForm1.SearchAndHighlightText(aText: string);
var
  i: Integer;
begin
  for i := 0 to WebBrowser1.OleObject.Document.All.Length - 1 do
  begin
    if Pos(aText, WebBrowser1.OleObject.Document.All.Item(i).InnerText) <> 0 then
    begin
      WebBrowser1.OleObject.Document.All.Item(i).Style.Color := '#FFFF00';
      WebBrowser1.OleObject.Document.All.Item(i).ScrollIntoView(True);
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  SearchAndHighlightText('some text...');
end;