The technical system of Mozilla is mainly divided into three to four levels, see the box part of the figure below: Let's start from the bottom level. Mozilla Platform Layer: Mozilla is a cross-platform project, so at the bottom, it is a platform adaptation layer for various operating systems, so that Mozilla can run on various system platforms. In addition to the adaptation layer of various OS, this layer also includes important engines such as Gecko, Necko, and some basic feature packages. (Gecko is a graphics rendering engine, Necko is a network engine). The development of this layer mainly uses C, and C . XPCOM LAYER: Blur of the platform layer, encapsulates the underlying function, and the components are used in the form of the other XPCOM components and the upper JavaScript call. XPCOM is very similar to COM, and the environment where COM registered is Windows, XPCOM registered environment is Mozilla, in addition, XPCOM has a set of book specifications. XPCOM's development language is mainly C ; XPCOM can also be developed with JavaScript, but it is relatively small. Mozilla has encapsulated a lot of practical XPCOM components, This book lists almost all components and their usage, http: //xulplanet.com/reference/xpcomref/, but this book seems to have not been updated. Chrome Layer: English is a metal "chrome", here is a name of the agreement and a general title to the mozillagui section. All interface applications are at this layer and the most colorful layer. We usually feel and exposed to the winter and winter realized by the Chrome layer. The interface layer defines a lot of interface components with XBL technology. We can also define your own interface components that use to define the frame structure of the interface, with JavaScript, CSS, RDF, etc. You can create a colorful interface. Effects, the document of the Chrome layer will finally become a JAR package according to the module, put it in the Chrome directory. The main development technology of Chrome layers is XUL / XBL, JavaScript, CSS, RDF, DTD, etc. The things of this layer I have specifically used as a Topic, and I will say it here. OK, Mozilla is roughly divided into such layers, each with the next layer, and each layer can be expanded and developed. This is a hierarchy of Mozilla transversely cutting. If longitudinally cut, Mozilla can be divided into a module (module), and the module is composed of a part of the XPcom plus a part of CHROME. For example, Browser is a module, and he is connected by browser.jar and the underlying network XPCOM component and other components; Email modules, and the interface part plus some POP3 and SMTP XPCOM components. These modules are not fixed, they can be developed by third parties, such as a lot of Firefox plugins, which are added to Firefox with different modules, which is also reflected in the path when visiting, Chrome : //xxxx/content/...xul, XXXX here is the name of Module. By the way, say why Mozilla is a development platform.
