1.05 The Development of the World Wide Web
The World Wide Web is one of the many services offered by the Internet. Developed by Tim Berners-Lee, it is so named because it represents an intricate maze connecting millions of computers containing billions of documents written in hypertext markup language (HTML).
Hypertext allows you to create links between documents located anywhere in the world on Web servers that are connected to the Internet backbone. By including hypermedia in your Web pages, you can link graphics, audio and video to other documents as well.
The success of the Internet and, ultimately the Web was dependent on developing a technology that allows dissimilar systems to be connected together. Researchers needed a means to connect mainframes with supercomputers and eventually with desktops all having different hardware configurations and operating systems.
Early connection interfaces were highly proprietary and unsuitable. As a result, the International Standards Organization (ISO) developed the Open Systems Interconnect Model, a standard model by which systems communicate across a network.
In order to communicate on the Internet, each computer must have a unique identifier called an IP address. Sometimes called the "dotted quad" an IP address is 32-bits and consists of four parts separated by decimal points.
Examples:
When you request a Web page in HTML format using the HTTP protocol, you get connected to your Internet Service Provider (ISP), which is the host that provides the physical connection to the Internet. Your ISP then connects you to the Web server or computer on which the page is stored. Every host and every server has at least one unique IP address.
In reality, the terms host and server are often used interchangeably. Though, technically, hosts provide the physical connection to the Internet backbone, they can be configured as servers while servers can be configured to provide multiple services. The important thing to remember is that an IP address is required for every physical connection regardless of the functions each computer performs.
The numeric IP addressing scheme is well suited to a machine designed to deal with numeric data. People, however, have a difficult time remembering such addresses. TCP/IP, which is a suite of protocols, formats and other services includes a Domain Name Service (DNS), allowing the use of more user-friendly names.
Every domain name used on the Internet must be unique, therefore must be registered. In North America, regulation of common top-level domains (com, edu, gov, net, org) is handled by the U.S. Department of Commerce and InterNIC (http://www.internic.net), a cooperative activity between the National Science Foundation (NSF), Network Solutions, Inc, and AT&T. You can register a domain name with many competing accredited registrars, such as Network Solutions (http://www.networksolutions.com).
Since residential ISPs typically won't allow you to set up a Web Server for people to access your Web pages due to bandwidth restrictions, you'll need to find a Web server host where you can upload your pages for the world to access. Hosting arrangements vary from free to monthly costs exceeding 1000's of dollars depending on the services you want to offer and on the bandwidth required. Some free hosting services include:
- Yahoo's Geocities (http://www.geocities.com/)
- 0catch (http://www.0catch.com/)
- NetFirms (http://www.netfirms.com/)
In order to display Web pages on a computer, users need a Web "browser." A browser is the application designed to interpret and render HTML code so that it is readable to the user. When hypertext was first introduced as a means for linking documents, numerous browsers were developed, all with their own proprietary programming. In other words, different browsers would interpret the HTML code differently making it difficult for Web page developers to control the appearance of their documents. While currently there are only two browsers that have gained any widespread popularity (Netscape Navigator and Internet Explorer), we still have the same compatibility problems.
In addition to programming issues, browsers are typically designed to be user configurable. Users can disable images from displaying, change the font size of text content and disable scripting languages that allow for interactivity. Users can also control screen colors by changing the true colors of a Web page to ones that are based on their operating system's palette. Unlike artists who create their masterpiece on a carefully chosen canvas with the appropriate medium, HTML provides Web designers with little real control over how their work is actually seen by the user.
HTML stands for Hypertext Markup Language and was developed as a means of distributing nonlinear text, called hypertext, to multiple points across the Internet. One document links to another through pointers called hyperlinks. Hyperlinks are embedded instructions within one text file that call another file whenever the link is accessed, usually by a click of a mouse. HTML is cross-platform compatible and works in Windows, Macintosh and on UNIX. As a markup language, HTML works different from a programming language in that the instructions and the data in HTML exist in the same file. HTML does not provide data structures or internal logic as do programming languages.
Version Date HTML 1.0 1989-1994 HTML 2.0 1995 HTML 3.0 1997 HTML 4.01 1999 XHTML 1.0 2001
1.08 Extensions, XML and the Future
With the browser as the "window to the Web," browser makers have attempted to "corner the market" by creating browsers that will only interpret its own proprietary code. Web page developers then need to learn the language of each browser in order to create any meaningful pages. Kind of like having to buy Ford gas to drive a Ford car. The function of the World Wide Web Consortium, or W3C (http://www.w3.org) is to promote the standardization of, amongst other things, HTML code and browser design.
Though great strides have been made toward this goal, the leading browser makers have been slow to conform to the recommendations of the W3C with Web developers still needing to write code specific to each browser in order for their pages to render correctly in either. Tim Berners-Lee, inventor of the Web is also credited as founder of the W3C in collaboration with CERN and supported by DARPA and the European Commission. Keep in mind that the W3C promotes standardization in all aspects of Internet technology on a global scale. It is organized into four domains based on the major activities in which it is involved:
- Architecture
- User Interface
- Technology and Society
- Web Accessibility
While much of the current work of the W3C is in promoting standardization, other issues have surfaced leading to advancements in markup language specifications. Because of the limitations posed by HTML, including lack of differentiation between presentation and content, lack of extensibility, and problems related to indexing and searching Web content, which makes HTML difficult to maintain and process, XML has been introduced as the next generation of Web code. XML stands for eXtensible Markup Language and departs from HTML in that XML tags deal with document structure, not presentation format. Some of the old and new leading edge technologies every Web designer needs to be familiar with include:
Name Description HTML
Hypertext Markup LanguageLanguage used to specify format of Web pages. DHTML
Dynamic Hypertext Markup LanguageAdds functionality to Web pages by inclusion of other technologies (i.e. JavaScript, CSS, DOM) CSS
Cascading Style SheetsA means of specifying document format and presentation. Gives the developer more control over page appearance than HTML. Can be used with HTML and XML. XSL
eXtensible Style LanguageStyle language specifically for use with XML. XHTML
eXtensible Hypertext Markup LanguageA reformulation of HTML 4 as a prelude to XML. Developed to provide transitional compatibility between the two languages. XSLT
eXtensible Style Language TransformationsXSLT is used to describe how to transform the source tree or data structure of an XML document into the result tree for a new XML document, which can be completely different in structure. XPath A language that describes a way to locate and process items in Extensible Markup Language (XML) documents by using an addressing syntax based on a path through the document's logical structure or hierarchy Any serious Web designer should also become familiar with the W3C and its role in building the Web of the future.
HTML files are plain text files that have been "marked up" with special language elements called tags. Tags are pieces of text, enclosed in angle brackets (less than and greater than signs) that provide instructions to programs designed to interpret HTML (i.e. browsers). You can create an HTML document in any text editor, including Windows Notepad. You can also use a word processing program provided you save your pages as plain text. Many designers choose to use programs that are specifically designed for creating and editing HTML pages such as Dreamweaver, Homesite, FrontPage or GoLive. In this course, you will learn to write your code manually using a text editor, which will be an invaluable skill when it comes times to fix things that don't work.