A web browser is a software package that enables a user to display and interact with HTML documents hosted by web servers. The largest networked collection of these documents is known as the World Wide Web.
Communication between the web server and the browser uses primarily the HTTP protocol. Most browsers also support other protocols, such as FTP, Gopher, and HTTPS (a SSL encrypted version of HTTP). Web browsers are able to retrieve documents stored in other file formats or in streams using these other protocols, but also using HTTP. This allows the author to embed images, animations, video and sound into a web page, or to make them accessible through the web page.
Some of the more popular browsers include additional components to support Usenet news and e-mail via the NNTP, IMAP and POP protocols. Most web browsers have the ability to save a file of bookmarks for sites the user has visited (or will often want to).
Early 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 Web interoperability. Modern web browsers (such as Mozilla, Opera, and Safari) support standards-based HTML and XHTML (starting with HTML 4.01), which should display in the same way across all browsers.
Web and web browser features
Different browsers can be distinguished from each other by the features they support. Modern browsers and web pages tend to utilise many features and techniques that did not exist in the early days of the web. Competition between Netscape and Microsoft for browser market-share in the mid 1990s helped oversee a rapid and chaotic expansion of browser and World Wide Web feature sets.
The following is a list of some of these elements and features:
- Ad filtering
- HTML Tables (HTML 3.02) and table color
- Framess and I-Frames
- Fonts (size, color) and cascading style sheets
- DHTML and XML
- Established graphics file formats such as PNG (ersatz for GIF), JPEG, SVG
- Session management
- Tabbed browsing