webbrowser

A web browser is a software application that retrieves, renders, and navigates information on the World Wide Web. It requests resources using HTTP or HTTPS, interprets markup languages such as HTML and XML, applies styles via CSS, and executes client-side scripts with JavaScript to present content to the user.

A browser comprises multiple components, including a rendering engine that builds the visual layout (for example Blink, WebKit, or Gecko), a networking stack for fetching resources, and a user interface that provides controls such as address bars, back/forward buttons, and tabs. It also stores data in cookies, caches, and local storage, and enforces security boundaries through sandboxing and other isolation mechanisms.

The browser implements web standards, supporting HTML, CSS, JavaScript, and numerous APIs for multimedia, graphics, and networking. It offers features such as tabbed browsing, bookmarks, history, downloads, and private or incognito modes. Many browsers support extensions or add-ons and provide developer tools for inspecting and debugging pages.

The modern browser landscape evolved from early tools such as Mosaic and Netscape Navigator to a variety of rendering engines, with Gecko, WebKit, and Blink playing major roles. Blink is used by Chromium-based browsers, WebKit by Safari, and Gecko by Firefox. Today, browsers from multiple vendors compete on speed, standards compliance, privacy, security, and ecosystem support.

Security and privacy are central concerns. Browsers update frequently to patch vulnerabilities, isolate processes, enforce same-origin policies, and block insecure content. Privacy features include private browsing, tracker blocking, and controls over cookies and site permissions.