BHO（浏览器辅助对象）是一种简单的ATL COM对象，而Internet Explorer会在每次运行时都加载它；换句话来说，即每个Internet Explorer的实例都会加载它。BHO运行在Internet Explorer的地址空间内，能对可访问的对象（如窗口、模块等等）执行任何操作，且因为它依附于浏览器的主窗口，所以其生命期与浏览器实例的生命期一致。-BHO (browser helper object) is a simple ATL COM object, but Internet Explorer will load each time when they run it　In other words, that each instance of Internet Explorer will load it. BHO run in Internet Explorer' s address space, can be accessed objects (such as windows, modules, etc.) to perform any operation, and because it is dependent on the browser' s main window, so its lifetime and the lifetime of the browser instance unanimously.