What Are Browser Helper Objects?
From this point of view, Internet Explorer is just like any other Win32-based program with its own memory space to preserve. With Browser Helper Objects you can write components—specifically, in-process Component Object Model (COM) components—that Internet Explorer will load each time it starts up. Such objects run in the same memory context as the browser and can perform any action on the available windows and modules. For example, a BHO could detect the browser’s typical events, such as GoBack, GoForward, and DocumentComplete; access the browser’s menu and toolbar and make changes; create windows to display additional information on the currently viewed page; and install hooks to monitor messages and actions. Before going any further with the nitty-gritty details of BHO, there are a couple of points I need to illuminate further. First, the BHO is tied to the browser’s main window. In practice, this means a new instance of the object is created as soon as a new browser window is creat
