• Web browser, a program used to access the World Wide Web
• Code browser, a program for navigating source code
• File browser or file manager, a program used to manage files and related objects
• Hardware browser, a program for displaying networked hardware devices
• Browser service, a feature of Microsoft Windows to browse shared network resources
• Browsing, a kind of orienting strategy in animals and human beings
• Browsing (herbivory), a type of feeding behavior in herbivores

A web browser (commonly referred to as a browser) is a software application for accessing information on 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. For a user, a search engine is just 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, laptops, tablets, and smartphones. In 2020, an estimated 4.9 billion people used a browser, with more than half of them in Asia. 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 [像PuTTY]; it was released in 1991. 1993 was a landmark year with the release of Mosaic, credited as "the world's first popular browser". Marc Andreessen, the leader of the Mosaic team, soon started his own company, Netscape, which released the Mosaic-influenced Netscape Navigator in 1994. Microsoft debuted Internet Explorer in 1995, leading to a browser war with Netscape.

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 Firefox, first released by Mozilla in 2004. Firefox reached a 28% market share in 2011. Apple released its Safari browser in 2003. Google 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 ever since. Microsoft released its Edge browser in 2015 as part of the Windows 10 release and rebuilt it as a Chromium-based browser in 2019. (Internet Explorer is still used on older versions of Windows.)

In terms of technology, browsers have greatly expanded their HTML, CSS, JavaScript, and multimedia capabilities since the 1990s. One reason has been to enable more sophisticated websites, such as web applications. 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 information resources from the Web and display them on a user's device.

This process begins when the user inputs a Uniform Resource Locator (URL), such as https://fanyi.baidu.com/, into the browser. Virtually all URLs on the Web start with either http: or https: which means the browser will retrieve them with the Hypertext Transfer Protocol (HTTP). In the case of https:, the communication between the browser and the web server is encrypted 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 and video formats supported by the browser. Web pages usually contain hyperlinks to other pages and resources. Each link contains a URL, and when it is clicked or tapped, 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.

An HTTP cookie (also called web cookie, Internet cookie, browser cookie, or simply cookie) is a small piece of data stored on the user's computer by the web browser while browsing a website. Cookies were designed to be a reliable mechanism for websites to remember stateful information (such as items added in the shopping cart in an online store) or to record the user's browsing activity (including clicking particular buttons, logging in, or recording which pages were visited in the past). They can also be used to remember pieces of information that the user previously entered into form fields, such as names, addresses, passwords, and payment card numbers.

During the course of browsing, browsing history cookies received from various websites 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.

Lynx is a customizable text-based web browser for use on cursor-addressable character cell terminals. As of 2020, it is the oldest web browser still being maintained, having started in 1992. Iceweasel is Debian's Firefox rebrand, and GNU IceCat is GNU's fork of Firefox. Waterfox is a Firefox-based web browser for Windows, macOS, and Linux.

A browser engine is a core software component of every major web browser. The primary job of a browser engine is to transform HTML documents and other resources of a web page into an interactive visual representation on a user's device. Layout engines:

• Gecko is developed by the Mozilla Foundation.
• KHTML is developed by the KDE project.
• Presto was developed by Opera Software for use in Opera. Development stopped as Opera transitioned to Blink.
• Trident is developed by Microsoft for use in the Windows versions of Internet Explorer 4 to Internet Explorer 11.
• EdgeHTML is the engine developed by Microsoft for Edge. It is a largely rewritten fork of Trident with all legacy code removed.
• WebKit is a fork of KHTML by Apple Inc. used in Apple Safari, and formerly in Chromium and Google Chrome.
• Blink is a 2013 fork of WebKit's WebCore component by Google used in Chromium, Google Chrome, Microsoft Edge, Opera, and Vivaldi.

Blink is a browser engine developed as part of the Chromium project (since 2013) with contributions from Google, Facebook, Microsoft, Opera Software, Adobe, Intel, IBM, Samsung, and others. It was first announced in April 2013. It's written in C++. Blink, Gecko, WebKit—these are millions of lines of code each.

六级/考研单词: web, browse, navigate, hardware, orient, herb, website, retrieve, necessity, seldom, confuse, install, desktop, laptop, billion, globe, notable, recruit, landmark, evolve, era, protocol, render, tap, thereby, download, stipulate, data, compute, cart, offline, log, password, credentials, fork, component, layout, opera, transition, blink, legacy, million

Firefox主题：Chrome仿真界面完全攻略 | ZWWoOoOo

Let's build a browser engine! Part 1: Getting started (limpet.net)