The main components of browsers include:
1. The user interface - including the address bar, back / forward buttons, bookmarks and other directory, which is what you see outside except to show the rest of the main window you requested page
2. The browser engine - used to query and rendering engine operating interface
3. rendering engine - used to display the contents of the request, for example, if the requested content is html, it is responsible for parsing html and css, and displays the result parsed
4. Network - the network to complete the call, e.g. http request, which has a platform-independent interface, can operate on different platforms
5. UI rear end - to draw substantially similar composition component selection boxes and dialog boxes, etc., having a common interface not specific to the underlying operating system using a user interface platform
6. The JS interpreter - the code used to explain the execution of the JS
7. Data storage - belong to persistence layer, the browser needs to save all kinds of data similar to a cookie on your hard drive, HTML5 defines a web database technology, which is full of a lightweight client-side storage techniques