uses mshtml, activex;

procedure GetHtmlCode(WebBrowser: TWebBrowser; FileName: string);
var
 htmlDoc: IHtmlDocument2;
 PersistFile: IPersistFile;
begin
 htmlDoc := WebBrowser.document as IHtmlDocument2;
 PersistFile := HTMLDoc as IPersistFile;
 PersistFile.save(StringToOleStr(FileName), true);
end;