Web Browser

Web Browsers are a type of software application used for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier (URI) and may be a web page, image, video, or other piece of content. Hyperlinks present in resources enable users to easily navigate their browsers to related resources.

Although browsers are primarily intended to access the World Wide Web, they can also be used to access information provided by web servers in private networks or files in file systems. Some browsers can also be used to save information resources to file systems.

Some examples of web browsers are Mozilla Firefox, Internet Explorer, Google Chrome, Safari, Konqueror, Opera, and Netscape.

Features
Available web browsers range in features from minimal, text-based user interfaces with bare-bones support for HTML to rich user interfaces supporting a wide variety of file formats and protocols. Browsers which include additional components to support e-mail, Usenet news, and Internet Relay Chat (IRC), are sometimes referred to as "Internet suites" rather than merely "web browsers".

All major web browsers allow the user to open multiple information resources at the same time, either in different browser windows or in different tabs of the same window. Major browsers also include pop-up blockers to prevent unwanted windows from "popping up" without the user's consent.

Most web browsers can display a list of web pages that the user has bookmarked so that the user can quickly return to them. Bookmarks are also called "Favorites" in Internet Explorer. In addition, all major web browsers have some form of built-in web feed aggregator. In Mozilla Firefox, web feeds are formatted as "live bookmarks" and behave like a folder of bookmarks corresponding to recent entries in the feed. In Opera, a more traditional feed reader is included which stores and displays the contents of the feed.

Furthermore, most browsers can be extended via plug-ins, downloadable components that provide additional features.

User interface
Most major web browsers have these user interface elements in common:


 * Back and forward buttons to go back to the previous resource and forward again.
 * 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.
 * 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.

Major browsers also possess incremental find features to search within a web page.

Privacy and security
Most browsers support HTTP Secure and offer quick and easy ways to delete the web cache, cookies, and browsing history.

Standards support
Early web browsers supported only a very simple version of HTML. The rapid development of 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.