A web browser (commonly referred to as a browser) is application software
for accessing the World Wide Web
. When a user
requests a web page
from a particular website
, the web browser retrieves the necessary content from a web server
and then displays the page on the user's device.
A web browser is not the same thing as a search engine
, though the two are often confused. A search engine is a website that provides links
to other websites. However, to connect to a website's server and display its web pages, a user must have a web browser installed.
Web browsers are used on a range of devices, including desktops
, and smartphone
s. In 2020, an estimated 4.9 billion people used a browser. The most used
browser is Google Chrome
, with a 63% global market share on all devices, followed by Safari
with 19%. Other notable browsers include Firefox
and Microsoft Edge
The first web browser, called WorldWideWeb
, was created in 1990 by Sir Tim Berners-Lee
. He then recruited Nicola Pellow
to write the Line Mode Browser
, which displayed web pages on dumb terminals
; it was released in 1991.
1993 was a landmark year with the release of Mosaic
, credited as "the world's first popular browser".
Its innovative graphical interface
made the World Wide Web system easy to use and thus more accessible to the average person. This, in turn, sparked the Internet boom of the 1990s, when the Web grew at a very rapid rate.
, the leader of the Mosaic team, soon started his own company, Netscape
, which released the Mosaic-influenced Netscape Navigator
in 1994. Navigator quickly became the most popular
debuted Internet Explorer
in 1995, leading to a browser war
with Netscape. Microsoft was able to gain a dominant position for two reasons: it bundled Internet Explorer with its popular Windows operating system
and did so as freeware
with no restrictions on usage. Eventually the market share of Internet Explorer peaked at over 95% in 2002.
In 1998, Netscape launched what would become the Mozilla Foundation
to create a new browser using the open source
software model. This work evolved into the Firefox
browser, first released by Mozilla in 2004. Firefox reached a 28% market share in 2011.
released its Safari
browser in 2003. It remains the dominant browser on Apple devices, though it did not become popular elsewhere.
debuted its Chrome
browser in 2008, which steadily took market share from Internet Explorer and became the most popular browser in 2012.
Chrome has remained dominant
In 2011, the HTTPS Everywhere extension
was released, and the NoScript
extension received numerous awards. The same year, Mozilla launched the stable version of Tor Firefox for navigating the dark web
Microsoft released its Edge
browser in 2015 as part of the Windows 10
release. (Internet Explorer is still used on older versions of Windows.)
In terms of technology, browsers have greatly expanded their HTML
, and multimedia
capabilities since the 1990s. One reason has been to enable more sophisticated websites, such as web application
s. Another factor is the significant increase of broadband
connectivity, which enables people to access data-intensive web content, such as YouTube streaming
, that was not possible during the era of dial-up modems
The purpose of a web browser is to fetch content from the Web
and display it on a user
This process begins when the user inputs a Uniform Resource Locator
(URL), such as ''
'', into the browser. Virtually all URLs on the Web start with either ''
'' or ''
'' which means the browser will retrieve them with the Hypertext Transfer Protocol
(HTTP). In the case of ''
'', the communication between the browser and the web server
for the purposes of security and privacy.
Once a web page
has been retrieved, the browser's rendering engine
displays it on the user's device. This includes image
formats supported by the browser.
Web pages usually contain hyperlink
s to other pages and resources. Each link contains a URL, and when it is clicked
, the browser navigates to the new resource. Thus the process of bringing content to the user begins again.
Most browsers use an internal cache
of web page resources to improve loading times for subsequent visits to the same page. The cache can store many items, such as large images, so they do not need to be downloaded from the server again. Cached items are usually only stored for as long as the web server stipulates in its HTTP response messages.
Web browsers can typically be configured with a built-in menu
. Depending on the browser, the menu may be named ''Settings'', ''Options'', or ''Preferences''.
The menu has different types of settings. For example, users can change their home page
and default search engine
. They also can change default web page
colors and font
s. Various network connectivity and privacy settings
are also usually available.
During the course of browsing, cookies
received from various website
s are stored by the browser. Some of them contain login credentials or site preferences.
However, others are used for tracking user behavior
over long periods of time, so browsers typically provide settings for removing cookies when exiting the browser.
Finer-grained management of cookies usually requires a browser extension
The most popular browsers have a number of features
in common. They allow users to set bookmarks
and browse in a private mode
. They also can be customized with extensions
, and some of them provide a sync service
Most browsers have these user interface
* Allow the user to open multiple pages
at the same time, either in different browser windows or in different tabs
of the same window.
* ''Back'' and ''forward'' buttons to go back to the previous page visited or forward to the next one.
* A ''refresh'' or ''reload'' and a ''stop'' button to reload and cancel loading the current page. (In most 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 URL
of a page 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.)
There are also niche browsers with distinct features. One example is text-only browsers
that can benefit people with slow Internet
connections or those with visual impairments.
Web browsers are popular targets for hacker
s, who exploit security holes
to steal information, destroy files
, and other malicious activities. Browser vendors regularly patch these security holes, so users are strongly encouraged to keep their browser software updated. Other protection measures are antivirus software
and avoiding known-malicious website
* Mobile browser
* List of web browsers
* Comparison of web browsers