CS 214 Lecture 02 - Familiarization With Web Tools

Introduction to Internet and HTML

LECTURE 2

CS 214: Introduction to Internet and HTML by Jayson G. Mauricio 2

Web Browser, a program that enables a computer to locate, download, and display documents containing text, sound, video, graphics, animation, and photographs located on computer networks. The act of viewing and moving about between documents on computer networks is called browsing. Users browse through documents on open, public-access networks called internets, or on closed networks called intranets. The largest open network is the Internet, a worldwide computer network that provides access to sites on the World Wide Web (WWW, the Web).


Browsers allow users to access Web information by locating documents on remote computers that function as Web servers. A browser downloads information over phone lines to a user’s computer through the user’s modem and then displays the information on the computer. Most browsers can display a variety of text and graphics that may be integrated into such a document, including animation, audio and video. Examples of browsers are:o Netscape o Internet Explorer o Mosaico Lynxo Netcruisero IBM Webexplorero Chameleon ando Hot Javao Firefox



http://www.w3schools.com/browsers


Browsers can create the illusion of traveling to an actual location in virtual space (hyperspace) where the document being viewed exists. This virtual location in hyperspace is referred to as a node, or a Web site. The process of virtual travel between Web sites is called navigating.


Documents on networks are called hypertext if the media is text only, or hypermedia if the media includes graphics as well as text.

Every hypertext or hypermedia document on an internet has a unique address called a uniform resource locator (URL).

Hypertext documents usually contain references to other URLs that appear in bold, underlined, or colored text. The user can connect to the site indicated by the URL by clicking on it. This use of a URL within a Web site is known as a hyperlink. When the user clicks on a hyperlink, the browser moves to this next server and downloads and displays the document targeted by the link. Using this method, browsers can rapidly take users back and forth between different sites.


Common features found in browsers include the ability to automatically designate a Web site to which the browser opens with each use, the option to create directories of favorite or useful Web sites, access to search engines (programs that permit the use of key words to locate information on the Internet, an internet or an intranet), and the ability to screen out certain types of information by blocking access to certain categories of sites.


A browser’s performance depends upon1. The speed and efficiency of the user’s computer, 2. The type of modem being used, and 3. The bandwidth of the data-transmission medium (the amount

of information that can be transmitted per second). Low bandwidth results in slow movement of data between source and recipient, leading to longer transmission times for documents.

4. Browsers may also have difficulty reaching a site during times of heavy traffic on the network or because of high use of the site.

The most commonly used browsers for the Web are available for free or for a small charge and can be downloaded from the Internet. Browsers have become one of the most important tools—ranking with e-mail—for computer network users. They have provided tens of millions of people with a gateway to information and communication through the Internet.


2010 IE8 IE7 IE6 Firefox Chrome

Safari Opera

May 16.0% 9.1% 7.1% 46.9% 14.5% 3.5% 2.2%

April 16.2% 9.3% 7.9% 46.4% 13.6% 3.7% 2.2%

March 15.3% 10.7% 8.9% 46.2% 12.3% 3.7% 2.2%

February

14.7% 11.0% 9.6% 46.5% 11.6% 3.8% 2.1%

January 14.3% 11.7% 10.2% 46.3% 10.8% 3.7% 2.2%


2009 IE8 IE7 IE6 Firefox Chrome Safari Opera

December

13.5% 12.8% 10.9% 46.4% 9.8% 3.6% 2.3%

November

13.3% 13.3% 11.1% 47.0% 8.5% 3.8% 2.3%

October 12.8% 14.1% 10.6% 47.5% 8.0% 3.8% 2.3%

September

12.2% 15.3% 12.1% 46.6% 7.1% 3.6% 2.2%

August 10.6% 15.1% 13.6% 47.4% 7.0% 3.3% 2.1%

July 9.1% 15.9% 14.4% 47.9% 6.5% 3.3% 2.1%

June 7.1% 18.7% 14.9% 47.3% 6.0% 3.1% 2.1%

May 5.2% 21.3% 14.5% 47.7% 5.5% 3.0% 2.2%

April 3.5% 23.2% 15.4% 47.1% 4.9% 3.0% 2.2%

March 1.4% 24.9% 17.0% 46.5% 4.2% 3.1% 2.3%

February

0.8% 25.4% 17.4% 46.4% 4.0% 3.0% 2.2%

January 0.6% 25.7% 18.5% 45.5% 3.9% 3.0% 2.3%CS 214: Introduction to Internet and HTML by Jayson G. Mauricio 12

2008 IE7 IE6 IE5 Firefox Chrome Safari OperaDecember

26.1% 19.6% 44.4% 3.6% 2.7% 2.4%

November

26.6% 20.0% 44.2% 3.1% 2.7% 2.3%

October 26.9% 20.2% 44.0% 3.0% 2.8% 2.2%September

26.3% 22.3% 42.6% 3.1% 2.7% 2.0%

August 26.0% 24.5% 43.7% 2.6% 2.1%July 26.4% 25.3% 42.6% 2.5% 1.9%June 27.0% 26.5% 0.5% 41.0% 2.6% 1.7%May 26.5% 27.3% 0.7% 39.8% 2.4% 1.5%April 24.9% 28.9% 1.0% 39.1% 2.2% 1.4%March 23.3% 29.5% 1.1% 37.0% 2.1% 1.4%February

22.7% 30.7% 1.3% 36.5% 2.0% 1.4%

January 21.2% 32.0% 1.5% 36.4% 1.9% 1.4%


2005 IE6 IE5Firefox

Mozilla

N7 O8 O7

November

62.7% 6.2% 23.6% 2.8% 0.4% 1.3% 0.2%

September

69.8% 5.7% 18.0% 2.5% 0.4% 1.0% 0.2%

July 67.9% 5.9% 19.8% 2.6% 0.5% 0.8% 0.4%

May 64.8% 6.8% 21.0% 3.1% 0.7% 0.7% 0.6%

March 63.6% 8.9% 18.9% 3.3% 1.0% 0.3% 1.6%

January 64.8% 9.7% 16.6% 3.4% 1.1% 1.9%


2002 IE6 IE5 AOL N3 N5 N4 IE4

November

53.5% 29.9% 5.2% 1.1% 4.9% 2.0%

September

49.1% 34.4% 4.5% 1.3% 4.5% 2.2%

July 44.4% 40.1% 3.5% 1.2% 3.5% 2.6% 0.5%

May 40.7% 46.0% 2.8% 1.2% 2.7% 3.4% 0.7%

March 36.7% 49.4% 3.0% 1.2% 2.4% 4.1% 0.7%

January 30.1% 55.7% 2.8% 1.3% 2.2% 4.4% 1.0%


IE Internet Explorer

FirefoxFirefox (identified as Mozilla before 2005)

Chrome Google Chrome

MozillaThe Mozilla Suite (Gecko, Netscape)

SafariSafari (and Konqueror. Both identified as Mozilla before 2007)

Opera / O

Opera

NNetscape (identified as Mozilla after 2006)

AOLAmerica Online (based on both Internet Explorer and Mozilla)


There was just one problem with the Web system – nobody could easily use the system effectively. In order for the system to work, one of two things had to happen. Either everyone would have to re-write, reformat, and re-save everything that was on the Internet so it pointed to everything else, or the programs that read this new Web format would have to be smart enough to deal with places on the Internet that the Web didn’t yet directly point to. Clearly, more breakthroughs were needed.

The first breakthrough came from a bunch of computer science

students and University of Illinois’ National Center for Supercomputing. They created a program called Mosaic that took these Web files, complete with links, and displayed them in a graphical window. It had the amazing ability to format the information in an appealing fashion that resembled professionally typeset text, and could display graphics along with the text.

To set them apart from the rest of information, links were

displayed with special formatting; and by clicking the link, the new information would appear automatically, regardless of where it was stored on the Internet.


As Mosaic matured, it created a huge following, partly because it was available for lots of different computers, partly because it was free, and partly because, well, it was so cool. Experienced Internet veterans were astounded at how easy it was to get information without having to know exactly where it was physically coming from. Mosaic emphasized the actual information, not the source. Beginners were amazed that it worked at all, because, as if by magic, it seemed to display text, graphics and later sounds and movies; they could actually click their way through the Internet without typing a single “weird” UNIX command.

Mosaic was also popular enough to essentially redefine how people

explained what the Web was. Before Mosaic, the Web was merely defined as an information-linking system. After Mosaic, the Web was described as anything that appeared with links highlighted and inline images within the Mosaic window: in other words, the Web was a collection of pages laid out in Mosaic.

Unfortunately, Mosaic was not without some serious problems. For starters,

it was a nightmare to set up and configure, had several serious bugs, and was so slow that it wasn’t practical unless the computer it was running on was directly wired to the Internet. Also, it only worked well when dealing with information on the Web: regular Internet services and information that hadn’t been converted over the Web format did not always look so good or work properly.




Netscape Communications Corporation, software company based in Mountain View, California. Netscape makes software that enables people to exchange information over the Internet and other computer networks. The company’s best-known software product, Navigator, allows computer users to browse the World Wide Web through a graphical user interface.

The company was founded in 1994 by James H. Clark, who started Silicon Graphics Inc. in 1982, and Marc Andreessen, a 22-year-old computer programmer. In 1993, as an undergraduate student at the University of Illinois at Urbana-Champaign and a staff member at the university’s National Center for Supercomputing Applications (NCSA), Andreessen led the development of a World Wide Web browser called NCSA Mosaic. Mosaic provided a point-and-click graphical interface that allowed computer users to explore text, images, and sound on the Internet much more easily than before. Distributed free over computer networks, Mosaic gained an estimated two million users in 18 months and launched the explosive growth of the Web.


In April 1994 Clark joined with Andreessen and several other members of the NCSA Mosaic programming team to found Mosaic Communications. Six months later the company released a Web browser, initially known simply as Netscape and later called Netscape Navigator, with capabilities that surpassed Mosaic’s. Netscape allowed Internet users to download Navigator for free, a move that encouraged the browser’s wide use. The company charged money for commercial versions of the product, which were purchased by corporations and those who wished to receive customer support. In December 1994 the company changed its name to Netscape Communications Corporation to avoid legal problems with the University of Illinois, which owned the Mosaic trademark. Clark hired Jim Barksdale, chief executive officer (CEO) of AT&T Wireless Services, as Netscape’s CEO in early 1995.


Netscape picks up where NCSA Mosaic left off. It installs easily, is supported by a professional software company (so bugs get fixed and features get added in response to customers, instead of NCSA’s method of updates which responded to academic pressures), and it works really well over a conventional modem connection. Best of all, it uses most standard Internet services and mimics many of the confusing UNIX-based text programs that most people find confusing.

In other words, Netscape truly integrates the hypertext-based World Wide Web with the older, conventional Internet formats that haven’t yet been-or will never be-converted to the Web’s HTML format. Netscape knows what to expect from older Internet services and assigns one hypertext links within them automatically in many cases you won’t even realize that you aren’t using a new, reformatted Web page.

Netscape also provides a layer of security for the information it reads and sends out. It can encode and decode Internet packets in such a way that no one but you and the intended recipient can use them, providing a safe way to actually buy and sell things through the Web with a credit card. With Mosaic, there is always a chance someone might be snooping in your transactions.


Other enhanced features include

High performance, even over a 14.4 modem, with simultaneous image and text loading and the ability to view and interact with information as it is retrieved.

Inline JPEG support. Easy bookmark menu creation, with sub-menus

and import/export capabilities. Support of Usenet newsgroups within the

Netscape window. A configurable graphical interface, and options

to make the best use a small or large monitor.CS 214: Introduction to Internet and HTML by Jayson G. Mauricio 24

Netscape let you use the majority of the services on the internet with the least amount of complexity, making the Internet a truly useful resource.

Navigator quickly became the standard Web browser. Within a year and a half of its introduction almost 40 million people, representing about 75 percent of the browser market, used the software to explore the Web. Netscape also developed software for servers to allow large companies to create internal networks called intranets. The software helped companies to manage databases, build Web sites, and conduct electronic commerce over the Internet. Netscape’s server software sold well, and the company’s overall sales jumped from $1.4 million in 1994 to $80.7 million in 1995.


In 1995 software giant Microsoft Corporation released a competing Internet browser called Internet Explorer. Microsoft bundled the product with its Windows operating system software and distributed it free over the Internet. Such tactics prompted Netscape to accuse Microsoft of anticompetitive behavior in a complaint to the United States Department of Justice. Although Microsoft denied the charges, the Justice Department launched an investigation.

In 1996 Netscape created Navio Communications, Inc., to develop Internet software based on Navigator technology for consumer electronic devices, such as televisions, telephones, and low-cost network computers. Netscape later agreed to merge Navio with Network Computer Inc., owned by Oracle Corporation, forming a new company called NCI. In 1997 Netscape released Communicator, a suite of programs that included Navigator, electronic-mail software, and other applications.



Microsoft Internet Explorer (MSIE) is the graphical World Wide Web browser or user interface that is provided with the Microsoft Windows 95 operating system. The MSIE browser is an alternative to the most popular Web browser, Netscape Navigator. (As of early January, 1998, 55% of our own visitors were using a Netscape browser and 40% were using Internet Explorer.)

Currently, the Justice Department is suing Microsoft to "unbundle" the Internet Explorer as part of Windows 95. Microsoft argues that because Web resources should be a natural part of the user interface, a Web browser should be part of a computer's operating system.



Lynx is a keyboard-oriented text-only Web browser that was developed at the University of Kansas primarily for students who used UNIX workstations. It has also been rewritten to run on VMS operating systems for users of VT100 terminals.

If you use the UNIX shell interface and your access provider offers it, Lynx may be interesting for you since it has a succinct key- (not mouse-) driven user interface. Information about Lynx, including where to download it, is available at the official Lynx server page.

