Web Browsers

Presented by Jahnvi Tanwar

What is a Web Browser ?A web browser or simple browser is software that acts as

an interface between the user and the internet specifically the www. They work on the client sever model and are sometimes referred to as web clients or universal clients. When a user loads a web browser it

• Contacts a web server and asks for the specified information.

• Receives the information and displays it on the screen.

Types of Web Browsers

A browser can be text based or graphical. A text based browser can display only text e.g. lynx. But the commonly used browsers today are all graphical i.e. they display graphics, images and multimedia. For example: Internet Explorer, Google chrome, Opera etc.

HistoryThe first web browser was invented in 1990 by Sir Tim Berners-Lee. Berners-Lee is the director of the World Wide Web Consortium (W3C), which oversees the Web's continued development, and is also the founder of the World Wide Web Foundation. His browser was called Worldwide Web and later renamed Nexus.The first commonly available web browser with a graphical user interface was Erwise. The development of Erwise was initiated by Rober Cailliau

Tim Berners Lee

FunctionThe primary purpose of a web browser is to bring information resources to the user, allowing them to view the information , and then access other information.This process begins when the user inputs a URL, for example http://en.wikipedia.org/, into the browser. The prefix of the URL, determines how the URL will be interpreted. The most commonly used kind of URL starts with http: and identifies a resource to be retrieved over the HTTP. Information resources may contain hyperlinks to other information resources. Each link contains the URI of a resource to go to. When a link is clicked, the browser navigates to the resource indicated by the link's target URI, and the process of bringing content to the user begins again.

Features

Web Browses have following features:• User interface• Privacy and security• Standards support• Extensibility

User interfaceMost major web browsers have these user interface elements in common:• Back and forward buttons to go back to the previous resource and forward

respectively.• A refresh or reload button to reload the current resource.• A stop button to cancel loading the resource. In some browsers, the stop

button is merged with the reload button.• A home button to return to the user's home page.• An address bar to input the Uniform Resource Identifier (URI) of the desired

resource and display it.• A search bar to input terms into a search engine. In some browsers, the

search bar is merged with the address bar.• A status bar to display progress in loading the resource and also the URI of

links when the cursor hovers over them, and page zooming capability.• The viewport, the visible area of the webpage within the browser window.• The ability to view the HTML source for a page.

Privacy and securityMost browsers support HTTP Secure and offer quick and easy ways to delete the web cache, cookies, and browsing history. For a comparison of the current security vulnerabilities of browsers, see comparison of web browsers.Standards supportEarly web browsers supported only a very simple version of HTML. The rapid development of proprietary web browsers led to the development of non-standard dialects of HTML, leading to problems with interoperability. Modern web browsers support a combination of standards-based and de facto HTML and XHTML, which should be rendered in the same way by all browsers.

ExtensibilityA browser extension is a computer program that extends the functionality of a web browser. Every major web browser supports the development of browser extensions.

Components

Web browsers consist of a user interface, layout engine, rendering engine, JavaScript interpreter, UI backend, networking component and data persistence component. These components achieve different functionalities of a web browser and together provide all capabilities of a web browser.

Some of the Famous Web Browsers

Opera

Opera is a web browser developed by Opera Software. The latest version is available for Microsoft Windows OSX, and Linux operating systems, and uses the Blink layout engine. An earlier version using the Presto layout engine is still supported, and additionally runs on FreeBSD systems. Editions of Opera are available for devices running the Android, iOS, Symbian, Maemo, Bada, BlackBerry and Windows Mobile operating systems, and for Java ME capable devices.According to Opera Software, the browser had more than 350 million users worldwide in the 4th quarter 2014.Total Opera mobile users reached 277 million in December 2014. Opera has been noted for originating many features later adopted by other web browsers. A prominent example is Speed Dial.

Internet Explorer

Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year. Later versions were available as free downloads, or in service packs, and included in the Original Equipment Manufacturer (OEM) service releases of Windows 95 and later versions of Windows.

Mozilla Firefox

Mozilla Firefox (known simply as Firefox) is a free and open-source web browser developed for Windows, OSX, and Linux, with a mobile version for Android, by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. Firefox uses the Gecko layout engine to render web pages, which implements current and anticipated web standards.

Google Chrome

Google Chrome is a freeware web browser developed by Google. It used the Web Kit layout engine until version 27 and, with the exception of its iOS releases, from version 28 and beyond uses the Web Kit fork Blink. It was first released as a beta version for Microsoft Windows on September 2, 2008, and as a stable public release on December 11, 2008.As of January 2015, Stat Counter estimates that Google Chrome has a 51% worldwide usage share of web browsers as a desktop browser. It is also the most popular browser for smart phones. Its success has led to Google expanding the 'Chrome' brand name on various other products such as the Chrome cast.Google releases the majority of Chrome's source code as an open-source project Chromium. A notable component that is not open source is the built-in Adobe Flash Player.

Netscape was the general name for a series of web browsers originally produced by Netscape Communications Corporation, now a subsidiary of AOL. The original browser was once the dominant browser in terms of usage share, but as a result of the first browser war, it lost virtually all of its share to Internet Explorer. Netscape was discontinued and support for all Netscape browsers and client products was terminated on March 1, 2008.

Netscape Navigator

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