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A browser is a group of structured codes that performs plenty of tasks to display a webpage on the screen. These codes are separated in to different components according to their tasks performed.
1. User Interface – It is the space where interaction between users and the browser occurs. Most of the browsers have common inputs for user interface. Some of them are - an address bar, next and back buttons, buttons for home, refresh and stop, options to bookmark web pages, etc. 2. Browser Engine – It is the piece of code that communicates the inputs of user interface with the rendering engine. It is responsible for querying and manipulating the rendering engine according to the inputs from various user interfaces. 3. Rendering Engine – It is the part thoroughly responsible for displaying the requested content on the screen. It first parses the html tags and then using the styles, it builds a render tree and finally a render layout, which displays the content on the screen. 4. Networking – The fraction of the code written in the browser, responsible to send various network calls. For example sending the http requests to the server. 5. Java Script Interpreter – It is the component of the browser written to interpret the java script code presented in a web page. 6. UI Backend – This draws basic widgets on the browser like combo boxes, windows, etc. 7. Data Storage – It is small database created on the local drive of the computer where the browser is installed. This database stores various files like cache, cookies, etc.
The main function of a browser is to present the web resource you choose, by requesting it from the server and displaying it in the browser window. The resource is usually an HTML document, but may also be a PDF, image, or some other type of content. The location of the resource is specified by the user using a URI (Uniform Resource Identifier).
The way the browser interprets and displays HTML files is specified in the HTML and CSS specifications. These specifications are maintained by the W3C (World Wide Web Consortium) organization, which is the standards organization for the web. For years browsers conformed to only a part of the specifications and developed their own extensions. That caused serious compatibility issues for web authors. Today most of the browsers more or less conform to the specifications.
Browser user interfaces have a lot in common with each other. Among the common user interface elements are:
Address bar for inserting a URI
Back and forward buttons
Bookmarking options
Refresh and stop buttons for refreshing or stopping the loading of current documents
Home button that takes you to your home pageAs you already know, to view a web site or a web page in a browser, you would either type in the URL or click on a link (as one in your Favorites/Bookmarks) and hit the Go button. Now, the page you have asked the browser to display would probably be located on a Server computer far far away. The web browser program sends a request (Could I have the web page please?) to a web server program running on the remote computer. Newbies may be baffled here due to similarity of names... the computer on which the web site is stored is called a Server (uppercase) and it runs a program (confusingly) also called a server (all small case).
Purists try to differentiate the computer (hardware) and program (software) by having the first letter in capitals (as in Server) but this is not a rule. Anyway, the server program, gathers the request from the web browser, tries to hunt for the web page and then formulates a response. This response will differ depending on whether the server program was able to find the requested web page or web file. Assuming, the server was able to locate the web page, it sends the HTML file to the web browser. The browser picks up all the information coming in from the server and does its best to display the web page. A typical web page not only has text but also images and these are separate files that need to be transferred from the server to the browser.
So the browser-server communication goes on till all the files have been transferred to the browser. Once the files arrive at your computer, the browser-server connection is severed - cut - chopped! If you now click on any link on this web page or even refresh the page, the process starts all over again. FYI, this is called the client-server architecture.
One important point remains - let us say you are looking at two different web pages of the same web site (such as ebay auctions) from two computers simultaneously using the same internet connection. How does the ebay server program know which page (and its associated images and other files) to send to which computer?
The answer to this seemingly complicated question lies in the request and response headerssent by the browser and server, respectively. So each request and response has a header that contains details such as the computer name (actually the I.P. address) so everything is in tune.
Finally, the information over the web is transferred using a set of rules called the HyperText Transfer Protocol (HTTP). Read more about this if you want to get you hand at details.
I think the main component of a browser is rendering engine because it allows the browser to display the elements of a Web page .
The most important thing in browser is rendering engine which is responsible of reading the web page code (html&css) and displaying it properly.
Also there is another this which is the javascript engine, which is responsible in reading the javascript code which is manipulating the page and performing requests and animations ...etc.
Controller, client program, interpreter
it is designing side and all the main function to perform a result of data base we use these HTM and css language.. client program.
I think the main components of a browser are,
Rendering Engine.
Java Script Engine.
Download Manager.
