The World Wide Web is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface. The World Wide Web is often abbreviated as the Web or WWW.
The World Wide Web was developed in 1989 by Tim Berners-Lee of the European Particle Physics Lab (CERN) in Switzerland. The initial purpose of the Web was to use networked hypertext to facilitate communication among its members, who were located in several countries. Word was soon spread beyond CERN, and a rapid growth in the number of both developers and users ensued. In addition to hypertext, the Web began to incorporate graphics, video, and sound. The use of the Web has reached global proportions and has become a defining aspect of human culture in an amazingly short period of time.
Almost every protocol type available on the Internet is accessible on the Web. Internet protocols are sets of rules that allow for intermachine communication on the Internet. The following is a sample of major protocols accessible on the Web:
newsgroups
Many other protocols are available on the Web. To name just one example, the Voice over Internet Protocol (VoIP) allows users to place a telephone call over the Web.
The World Wide Web provides a single interface for accessing all these protocols. This creates a convenient and user-friendly environment. Once upon a time, it was necessary to be conversant in these protocols within separate, command-level environments. The Web gathers these protocols together into a single system. Because of this feature, and because of the Web's ability to work with multimedia and advanced programming languages, the Web is by far the most popular component of the Internet.
HYPERTEXT AND LINKS: THE MOTION OF THE WEB
The operation of the Web relies primarily on hypertext as its means of information retrieval. HyperText is a document containing words that connect to other documents. These words are called links and are selectable by the user. A single hypertext document can contain links to many documents. In the context of the Web, words or graphics may serve as links to other documents, images, video, and sound. Links may or may not follow a logical path, as each connection is created by the author of the source document. Overall, the Web contains a complex virtual web of connections among a vast number of documents, graphics, videos, and sounds.
Producing hypertext for the Web is accomplished by creating documents with a language called HyperText Markup Language, or HTML. With HTML, tags are placed within the text to accomplish document formatting, visual features such as font size, italics and bold, and the creation of hypertext links. Graphics may also be incorporated into an HTML document.
HTML is an evolving language, with new tags being added as each upgrade of the language is developed and released. For example, visual formatting features are now often separated from the HTML document and placed into Cascading Style Sheets (CSS). This has several advantages, including the fact that an external style sheet can centrally control the formatting of multiple documents. The World Wide Web Consortium (W3C), led by Web founder Tim Berners-Lee, coordinates the efforts of standardizing HTML. The W3C now calls the language XHTML and considers it to be an application of the XML language standard.
PAGES ON THE WEB
The World Wide Web consists of files, called pages or Web pages, containing information and links to resources throughout the Internet.
Web pages can be created by user activity. For example, if you visit a Web search engine and enter keywords on the topic of your choice, a page will be created containing the results of your search. In fact, a growing amount of information found on the Web today is served from databases, creating temporary Web pages "on the fly" in response to user queries.
Access to Web pages may be accomplished by:
RETRIEVING DOCUMENTS ON THE WEB: THE URL and DOMAIN NAME SYSTEM
URL stands for Uniform Resource Locator. The URL specifies the Internet address of a file stored on a host computer connected to the Internet. Every file on the Internet, no matter what its access protocol, has a unique URL. Web browsers use the URL to retrieve the file from the host computer and the specific directory in which it resides. This file is downloaded to the user's client computer and displayed on the monitor connected to the machine.
URLs are translated into numeric addresses using the Domain Name System (DNS). The DNS is a worldwide system of servers that stores location pointers to Web sites. The numeric address, called the IP (Internet Protocol) address, is actually the "real" URL. Since numeric strings are difficult for humans to use, alphneumeric addresses are employed by end users. Once the translation is made by the DNS, the browser can contact the Web server and ask for a specific file located on its site.
Anatomy of a URL
This is the format of the URL:
protocol://host/path/filename
For example, this is a URL on the Web site of the U.S. House of Representatives:
http://www.house.gov/house/2004_House_Calendar.html
This URL is typical of addresses hosted in domains in the United States.
Structure of this URL:
Note how much information about the content of the file is present in this well-constructed URL.
New domain names were approved in November 2000 by the Internet Corporation for Assigned Names and Numbers (ICANN): .biz, .museum, .info, .pro (for professionals) .name (for individuals), .aero (for the aerospace industry), and .coop (for cooperatives). ICANN continues to investigate proposals for addding additional domain names, for example, .mobi for sites designed for mobile devices, and .jobs for the human resources community.
In addition, dozens of domain names have been assigned to identify and locate files stored on host computers in countries around the world. These are referred to as two-letter Internet country codes, and have been standardized by the International Standards Organization as ISO 3166.
As the technology of the Web evolves, URLs have become more complex. This is especially the case when content is retrieved from databases and served onto Web pages. The resulting URLs can have a variety of elaborate structures, for example,
http://spills.incidentnews.gov/incidentnews/FMPro?-db=images&-Format=maps.htm
&SpillLink=8&Subject=Waterway%20Closure%20Map&-SortField=EntryDate&
-SortOrder=descend&-SortField=EntryTime&-SortOrder=descend&-Token=8&
-Max=20&-Find
The first part of this URL looks familiar. What follows are search elements that query the database and determine the order of the results. As a growing number of databases serve content to the Web, these types of URLs are appearing more commonly in your browser's address window.
HOW TO ACCESS THE WORLD WIDE WEB: WEB BROWSERS
To access the World Wide Web, you must use a Web browser. A browser is a software program that allows users to access and navigate the World Wide Web. There are two types of browsers:
You can install a graphical browser on your computer. For example, Internet Explorer is a part of the Windows operating system, and is also available on the Microsoft site: http://www.microsoft.com/. Firefox is available for downloading from http://www.mozilla.org/products/firefox/ and Safari is available from http://www.apple.com/safari/.
Extending the Browser: Plug-Ins
Software programs may be configured to a Web browser in order to enhance its capabilities. When the browser encounters a sound, image or video file, it hands off the data to other programs, called plug-ins, to run or display the file. Working in conjunction with plug-ins, browsers can offer a seamless multimedia experience. Many plug-ins are available for free.
File formats requiring plug-ins are known as MIME types. MIME stands for Multimedia Internet Mail Extension, and was originally developed to help e-mail software handle a variety of binary (non-ASCII) file attachments. The use of MIME has expanded to the Web. For example, the basic MIME type handled by Web browsers is text/html associated with the file extention .html.
A common plug-in utilized on the Web is the Adobe Acrobat Reader. The Acrobat Reader allows you to view documents created in Adobe's Portable Document Format (PDF). These documents are the MIME type "application/pdf" and are associated with the file extension .pdf. When the Acrobat Reader has been downloaded to your computer, the program will open and display the file requested when you click on a hyperlinked file name with the suffix .pdf. The latest versions of the Acrobat Reader allow for the viewing of documents within the browser window.
Web browsers are often standardized with a small suite of plug-ins, especially for playing multimedia content. Additional plug-ins may be obtained at the browser's Web site, at special download sites on the Web, or from the Web sites of the companies that created the programs.
Once a plug-in is configured to your browser, it will automatically launch when you choose to access a file type that it uses.
Beyond Plug-Ins: Active X
ActiveX is a technology developed by Microsoft which make plug-ins less neccesary. ActiveX offers the opportunity to embed animated objects, data, and computer code on Web pages. A Web browser supporting ActiveX can render most items encountered on a Web page. As just one example, Active X allows you to view and edit PowerPoint presentations directly within your Web browser. ActiveX works best with Microsoft's Internet Explorer.
THE EXPERIENCE OF THE WEB
Today's World Wide Web presents an ever-diversified experience of multimedia, programming languages, and real-time communication. There is no question that it is a challenge to keep up with the rapid pace of developments. The following presents a brief description of some of the more important trends to watch.
Multimedia
The Web has become a broadcast medium. It is possible to listen to audio and video over the Web, both pre-recorded and live. For example, you can visit the sites of news organizations and view the same videos shown on the nightly news. Several plug-ins are available for viewing these videos.
At one time, the entire multimedia file had to be downloaded before viewing. Since these types of files tend to be quite large, download times can be lengthy. This problem has been answered by a revolutionary development in multimedia capability: streaming media. In this case, audio or video files are played as they are downloading, or streaming, into your computer. Only a small wait, called buffering, is necessary before the file begins to play.
The Windows Media Player, RealPlayer and QuickTime plug-ins play streaming audio and video files. Extensive files such as interviews, speeches, hearings televised video clips and music work very well with these players. They are also ideal for the broadcast of real-time events. These may include live radio and television broadcasts, concerts, Web-only broadcasts, and so on.
Shockwave and Flash are plug-ins that provide another multimedia experience. They offer the creation and implementation of an entire multimedia display combining graphics, animation and sound.
Sound files, including music, are also a part of the Web experience. Sound files may be incorporated into Web sites, and are also available for downloading independent of Web site visits. For example, try the search engine FindSounds.com. Sound files of many types are supported by the Web with the appropriate plug-ins. The MP3 file format, and the choice of supporting plug-ins, is one of the most popular music trends to sweep the Web.
MP3 files are also the source of podcasts. These are audio files distributed through RSS feeds. A good example of library podcasting can be found on the site of Dowling College, which distributes podcasts of interest to its user community. A variation on the podcast is the vodcast, which is a video file distributed through RSS. This type of multimedia broadcasting is up-and-coming on the Web. (More on RSS below.)
Live cams are another aspect of the multimedia experience available on the Web. Live cams are video cameras that send their data in real time to a Web server. These cams may appear in all kinds of locations, both serious and whimsical: an office, on top of a building, a scenic locale, a special event, and so on.
Programming Languages and Functions
The use of existing and new programming languages have extended the capabilities of the Web. What follows is a basic guide to a group of the more common languages and functions in use on the Web today.
CGI, Active Server Pages: CGI (Common Gateway Interface) refers to a specification by which programs can communicate with a Web server. A CGI program, or script, is any program designed to accept and return data that conforms to the CGI specification. The program can be written in any programming language, including C, Perl, and Visual Basic Script. A common use for a CGI script is to process a form on a Web page. For example, you might fill out a form to order a book at Amazon. The script processes your information and sends it to Amazon to process your order.
another type of dynamically generated Web page is called Active Server Pages (ASP). Developed by Microsoft, ASP is a programming environment that processes scripts on the Web server. The scripts run on the server, rather than on the Web browser, to generate the HTML pages sent to browsers. Visual Basic and JScript (a subset of JavaScript) are often used for the scripting. ASPs end in the file extension .asp or .aspx.
Java/Java Applets: Java Java is an object-oriented programming language similar to C++. Developed by Sun Microsystems, the aim of Java is to create programs that will be platform independent. The Java motto is, "Write once, run anywhere." A perfect Java program should work equally well on a PC, Macintosh, Unix, and so on, without any additional programming. This goal has yet to be realized. Java can be used to write applications for both Web and non-Web use.
Web-based Java applications are usually in the form of Java applets. These are small Java programs called from an HTML page that can be downloaded from a Web server and run on a Java-compatible Web browser. A few examples include live newsfeeds, moving images with sound, calculators, charts and spreadsheets, and interactive visual displays. Java applets can tend to load slowly, but programming improvements should lead to a shortened loading time.
JavaScript/JScript: JavaScript is a programming language created by Netscape Communications. Small programs written in this language are embedded within an HTML page, or called externally from the page, to enhance the page's the functionality. Examples of JavaScript include moving tickers, drop-down menus, real-time calendars and clocks, and mouse-over interactions. JScript is a similar language developed by Microsoft and works with the company's Internet Explorer browser.
XML: XML (eXtensible Markup Language) is a mark-up language that enables Web designers to create their own customized tags to provide functionality not available with HTML alone. XML is a language of data structure and exchange, and allows developers to separate form from content. With XML, the same content can be formatted for multiple applications. In May 1999, the W3 Consortium announced that HTML 4.0 has been recast as an XML application called XHTML. This move is slowing having an impact on the future of both XML and HTML.
Ajax: Ajax stands for Asynchronous JavaScript and XML. This langauge creates interactive Web applications. Its premise is that it sends data to the browser behind the scenes, so that when it is time to view the information, it is already "there." Google Maps is an example of an Ajax-enabled application. Another is SurfWax LookAhead, an RSS search tool that retrieves feeds as you type your query.
Real-Time Communication
Text, audio and video communication can occur in real time on the Web. This capability allows people to conference and collaborate in real time. In general, the faster the Internet connection, the more successful the experience.
At its simplest, chat programs allow multiple users to type to each other in real time. Internet Relay Chat and America Online's Instant Messenger are prime examples of this type of program. The development of a messenging protocols is underway. Such a protocol would allow for the expansion of this capability throughout the Internet.
More enhanced real-time communication offers an audio and/or video component. CU-See Me is a sotware programs of this type. Even more elaborate are programs that allow for true real-time collaboration. Microsoft's NetMeeting and Netscape's Conference (available with Communicator) are good examples of this.
Featured collaboration tools include:
Currently no standard exists that will work among all conferencing programs.
Current Trends: Blogs and RSS
The Web is a welcoming medium for experimentation and user participation. It is becoming easier to post Web content and share comments with other users. The idea of the Web site is still very much alive, but Web participation is taking new forms and being driven by new technologies that foster social interaction. Here are two of the latest trends.
Blogs: A blog is an easy-to-create Web site that allows users to share their thoughts with the world managed by a lightweight content management system. The word "blog" comes from "Weblog" because a blog consists of a signed and dated log of individual postings. The topic of the blog can be anything, from the personal to the professional. A blog is what you make of it.
What is important about blogs is the content management system that manages the content. This system can offer a variety of features that can make the blog a useful tool. Examples include a calendar view of postings, organization of postings into categories, archived postings, options to send e-mail notification of new postings, and so on.
Blogging can be an interactive activity. Readers can add comments to a blogger's postings, other can respond, and a conversation ensues. Lately, bloggers have become well-known commentators on the political scene, but blogging can encompass any topic or no topic at all. If the blogging software allows it, bloggers can use RSS to distribute their postings.
Visit Technorati, a search engine devoted to locating blogs. You can set up your own blog by visiting Blogger.
RSS: RSS allows people to place news and other announcement-type items into a simple XML format that can then be pushed to RSS readers and Web pages. The initials RSS can stand for different things, including Rich Site Summary or Really Simple Syndication. Users can subscribe to the RSS newsfeeds of their choice, and then have access to the updated information as it comes in. RSS is used for all kinds of purposes, including the news itself and announcing new content on Web sites.
RSS content may be read by using an RSS reader, or aggregator. This is usually free software that you can install on your computer that posts new items and stores old ones in a graphical interface. An RSS reader similar to e-mail software in that it displays incoming items and can store content for offline reading. Subscribing to a newsfeed is usually as simple as entering the address of the RSS document.
A useful list of RSS readers is available on the site of RSS Compendium.
It is also possible to subscribe to and read your own collection of RSS feeds on Web sites devoted to this purpose. Bloglines is one such example. The advantage here is that you can access your RSS feeds from any computer that is connected to the Web.
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