conceptos generales

General Concepts 

What is browser mean?

A browser is an application program that provides a way to look at and interact with all the information on the World Wide Web. The word "browser" seems to have originated prior to the Web as a generic term for user interfaces that let you browse (navigate through and read) text files online.

Technically, a Web browser is a client program that uses HTTP (Hypertext Transfer Protocol) to make requests of Web servers throughout the Internet on behalf of the browser user. Most browsers support e-mail and the File Transfer Protocol (FTP) but a Web browser is not required for those Internet protocols and more specialized client programs are more popular.

The first Web browser, called WorldWideWeb, was created in 1990. That browser's name was changed to Nexus to avoid confusion with the developing information space known as the World Wide Web. The first Web browser with a graphical user interface was Mosaic, which appeared in 1993. Many of the user interface features in Mosaic went into Netscape Navigator. Microsoft followed with its Internet Explorer(IE).

Browser types

Internet Explorer

Internet Explorer (IE) is a product from software giant Microsoft. This is the most commonly used browser in the universe. This was introduced in 1995 along with Windows 95 launch and it has passed Netscape popularity in 1998.

Google Chrome

This web browser is developed by Google and its beta version was first released on September 2, 2008 for Microsoft Windows. Today, chrome is known to be one of the most popular web browser with its global share of more than 50%.

Mozilla Firefox

Firefox is a new browser derived from Mozilla. It was released in 2004 and has grown to be the second most popular browser on the Internet.

Safari

Safari is a web browser developed by Apple Inc. and included in Mac OS X. It was first released as a public beta in January 2003. Safari has very good support for latest technologies like XHTML, CSS2 etc.

Opera

Opera is smaller and faster than most other browsers, yet it is full- featured. Fast, user-friendly, with keyboard interface, multiple windows, zoom functions, and more. Java and non Java-enabled versions available. Ideal for newcomers to the Internet, school children, handicap and as a front-end for CD-Rom and kiosks.

Konqueror

Konqueror is an Open Source web browser with HTML 4.01 compliance, supporting Java applets, JavaScript, CSS 1, CSS 2.1, as well as Netscape plugins. This works as a file manager as well as it supports basic file management on local UNIX filesystems, from simple cut/copy and paste operations to advanced remote and local network file browsing.

Lynx

Lynx is a fully-featured World Wide Web browser for users on Unix, VMS, and other platforms running cursor-addressable, character-cell terminals or emulators.

Links

 Is an open source text and graphic web browser with a pull-down menu system. It renders complex pages, has partial HTML 4.0 support (including tables and frames and support for multiple character sets such as UTF-8), supports color and monochrome terminals and allows horizontal scrolling.

It is intended for users who want to retain many typical elements of graphical user interfaces (pop up windows, menus etc.) in a text-only environment.

The original version of Links was developed by Mikuláš Patočka in the Czech Republic. His group, Twibright Labs, later developed version 2 of the Links browser, that displays graphics, renders fonts in different sizes (with spatial anti-aliasing) but does not support JavaScript any more (it used to, up to version 2.1pre28). The resulting browser is very fast, but it does not display many pages as they were intended. The graphical mode works even on Unix systems without the X Window System or any other window environment, using either SVGALib or the framebuffer of the system's graphics card.

URL

A Uniform Resource Locator (URL), colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifier (URI),although many people use the two terms interchangeably. URLs occur most commonly to reference web pages (http), but are also used for file transfer (ftp), email (mailto), database access (JDBC), and many other applications.

Most web browsers dislay the URL of a web page above the page in an address bar. A typical URL could have the form http://www.example.com/index.html, which indicates a protocol (http), a hostname (www.example.com), and a file name (index.html).

Uniform Resource Locators were defined in RFC  in 1994 by Tim Berners-Lee, the inventor of the World Wide Web, and the URI working group of the Internet Engineering Task Force (IETF), as an outcome of collaboration started at the IETF Living Documents Birds of a feather session in 1992.

The format combines the pre-existing system of domain names (created in 1985) with file path syntax, where slashes are used to separate directory and filenames. Conventions already existed where server names could be prefixed to complete file paths, preceded by a double slash (//).

Berners-Lee later expressed regret at the use of dots to separate the parts of the domain name within URIs, wishing he had used slashes throughout, and also said that, given the colon following the first component of a URI, the two slashes before the domain name were unnecessary.

An early (1993) draft of the HTML Specification referred to "Universal" Resource Locators. This was dropped some time between June 1994  and October 1994 (draft-ietf-uri-url-08.txt).

WEB ADDRESS PARTS 

The "http:" indicates what type of protocol you need to view this item. The protocol is the way in which two systems communicate. Examples of other protocols are ftp or telnet.

The "www" stands for World Wide Web. This is the name of the "host" computer where the web page is stored and is a common name given to computers connected to the web. However, it's not necessary for web addresses to begin with "www." The web page might also be stored on a host computer or server named something else.

The domain name is "oit.edu" and indicates that this page is coming from Oregon Institute of Technology. "Libraries" further directs the address to the Oregon Tech Library.

The part of the domain that is considered the top-level domain designator is the .edu. The most common types of top-level domains are:

.edu	Educational Institution	Besides the institution's official web pages, students or faculty members can also publish personal pages on these web sites.
.com	Commercial Entity	Anyone, anywhere in the world can have this type of web site. This is the most common type of site for companies and is often used to advertise and sell products, as well as to post company annual reports and other financial information. Online journals or newspapers also have .com web pages.
.org	Organization	This designation is used for any type of organization, including nonprofit organizations.
.net	Network Provider, etc.	Originally designated for organizations directly involved in Internet organizations, .net can now be used by anyone -- companies, organizations, and individuals. It is often used by businesses when the desired name under ".com" is already registered by another organization.
.gov	Government	Originally only for the federal government, .gov is now used for any level of government. These sites are used to publish tax forms, census information, legislation, and other government news or information.