Actually I know window class name I need. And in fact AutoHotkey has the Spy in its distro for this purpose. What I don't know is which function of AutoHotkey determines the class of window under cursor. I mean not the window like IE window itself, but rather control's window (InternetExplorer_Server for instance).
In other word: I want Autohotkey to run the aforementioned macro if the mouse is over WebBrowser control (InternetExplorer_Server class) in any application (IE, HtmlHelp, Visual Studio, etc.). Is this possible? If yes, then which function I should use?