procedure TWebModule1.WebModule1WebActionItem1Action(Sender: TObject;
  Request: TWebRequest; Response: TWebResponse; var Handled: Boolean);
begin
   if System.IsConsole then
     Response.Content := 'True'
   else
     Response.Content := 'False';
end;

if System.IsConsole then
   // do this
else
   // do that

if IsConsole then
   WriteLn('this')
;