The responsibility of the rendering engine is well. They will be discussed in a special chapter. I will devote a chapter for each of these components.Д«oth Firefox and Chrome developed a special communication infrastructures. It is important to note that Chrome, unlike most browsers, holds multiple instances of the rendering engine - one for each tab. The new HTML specification (HTML5) defines 'web database' which is a complete (although light) database in the browser. The browser needs to save all sorts of data on the hard disk, for examples, cookies. Used to parse and execute the JavaScript code. Underneath it uses the operating system user interface methods. It exposes a generic interface that is not platform specific. UI backend - used for drawing basic widgets like combo boxes and windows.It has platform independent interface and underneath implementations for each platform.

Networking - used for network calls, like HTTP requests.

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.

The rendering engine - responsible for displaying the requested content.

The browser engine - the interface for querying and manipulating the rendering engine.

Every part of the browser display except the main window where you see the requested page.

The user interface - this includes the address bar, back/forward button, bookmarking menu etc.

The browser's main components are ( 1.1): More on that in the user interface chapter. There are, of course, features unique to a specific browser like Firefox downloads manager. Among those are the address bar, status bar and tool bar. The HTML5 specification doesn't define UI elements a browser must have, but lists some common elements. Strangely enough, the browser's user interface is not specified in any formal specification, it is just good practices shaped over years of experience and by browsers imitating each other.

Home button that gets you to your home page.

A refresh and stop buttons for refreshing and stopping the loading of current documents.Among the common user interface elements are: Today most of the browsers more or less conform to the specifications.Д«rowsers' user interface have a lot in common with each other. That caused serious compatibility issues for web authors. The current CSS version is 2 ( ) and version 3 is in progress.ДЇor years browsers conformed to only a part of the specifications and developed their own extensions. These specifications are maintained by the W3C (World Wide Web Consortium) organization, which is the standards organization for the web. The way the browser interprets and displays HTML files is specified in the HTML and CSS specifications. The location of the resource is specified by the user using a URI (Uniform resource Identifier). The resource format is usually HTML but also PDF, image and more. The browser main functionality is to present the web resource you choose, by requesting it from the server and displaying it on the browser window. So nowdays open source browsers are a substantial part of the browser business. I will give examples from the open source browsers - Firefox,Chrome and Safari, which is partly open source.ДЄccording to the W3C browser statistics, currently(October 2009), the usage share of Firefox, Safari and Chrome together is nearly 60%. There are five major browsers used today - Internet Explorer, Firefox, Safari, Chrome and Opera.

We will see what happens when you type '' in the address bar until you see the Google page on the browser screen. In this book I will explain how they work behind the scenes. Web browsers are probably the most widely used software.

Current version of firefox uses css