Explain about the structure of modern browser with block diagram.

Structure of Web Browser

Fig: Structure of Web Browsers

All the modern browsers have following parts:

1. The user interface - This consists of  the address bar, back/forward button, bookmarking menu etc. Every part of the browser display except the main window where you see the requested page.
2. The browser engine - The browser engine performs the actions between the UI and the rendering engine.
3. The rendering engine - It is responsible for displaying the requested content. For example if the requested content is HTML, it is responsible for parsing the HTML and CSS and displaying the parsed content on the screen.
4. Networking - It is used for network calls, like HTTP requests. It has platform independent interface and underneath implementations for each platform.
5. UI backend - It is used for drawing basic widgets like combo boxes and windows. It exposes a generic interface that is not platform specific. Underneath it uses the operating system user interface methods.
6. JavaScript interpreter. It is used to parse and execute the JavaScript code.
7. Data storage. The browser needs to save all sorts of data on the hard disk, for examples, cookies. The new HTML specification (HTML5) defines 'web database' which is a complete (although light) database in the browser.This is a persistence layer.