A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web(WWW). An information resource is identified by a Uniform Resource Identifier(URL), which may be a web page, image, video, or another piece of content. Hyperlinks present in resources enable users easily to navigate their browser to related resources.
Functions of a web browser:
Although browsers are primarily intended to use the WWW they can also be used to access information provided by the web servers in private networks or files in file systems. The WWW is a system of internet servers that support specially formatted documents. Web browsers are used to make it easy to access the WWW. Browsers are able to display web pages largely in part to an underline web protocol called HyperText Transfer Protocol(HTTP). HTTP defines how messages are formatted and transmitted and what actions web servers and browsers should take in response to various commands. When we enter a web address (URL) in the browsers it actually sends an HTTP command to the webserver directly to fetch and transmit the information in the browser.
A web browser is actually a software app that runs on an internet-connected computer. It allows us t view web pages as well as use other content and technologies such as video, graphic files, and digital certificates to name a few. Some browsers will translate only text while others do graphical animation. Web browsers are not all created equal and web pages also will not be displayed the same in a different browser.
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Architecture of a web browser:
The browser’s main functionality is to fetch the file from the server and to display them on the screen.it basically displays HTML files containing images, PDF, videos, flashes, etc in an ordered layout. A browser is a group of structured code that performs a group of tasks to display a web page. These codes are separated into different components according to their task performed.
User interface:
The user interface is the space where interaction between users and the browser occurs. Most of the browsers have common inputs for the user interface. Some of them are an address bar, next and back button, home button, refresh and stop button, etc.
Browse Engine:
It is the peace of code that communicates the inputs of the user interface with the rendering engine. It is responsible for querying and manipulating the rendering engine according to the inputs from various user interfaces.
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 deals with a render tree and finally a render layout that displays the content on the screen.
Networking:
The function of the code written in the browser is responsible to sent various network calls. For example, sending the HTTP request to the server.
JavaScript Interceptor:
It is the component of the browsers written to interpret the javascript code presented on a web page.
UI Backend:
This draws basic widgets on the browser like combo boxes, windows, etc. The rendering engine uses the UI backend layer during the layout and painting stages to display the web page on the browser.
Data Persistence:
It is a small database created on the local file system of the computer where the browser is installed. The database stores various files like Cache, Cookies etc.