The WEB gives its users access to information on the Internet via a hypertext interface. This style of interface and the resulting ease of accessing information has probably been one of the main reasons for the rapid growth of the Internet.
The ideas of computer aided instruction and hypetext systems have been around for atleast the last two decades, so why the sudden excitement?
Its everywhere.
Yes, but isn't the WEB just good for surfing?
Good question.
One of the main advantages of the WEB is its ability to provide a common interface to a set of online documents. Typically documents are:
These types of documents occur frequently in CS and EE.
The WEB is really a set of specifications describing a protocol for the presentation of hypertext documents and a means of referencing documents via the Internet. Thus, the WEB is similar to X-windows, in that its the protocol that is important, not the actual browsers or servers.
The structure of a WEB document is specified by HTML (Hyper Text Markup Language). Anyone familar with LaTeX or Scribe would find HTML easy to learn. HTML is however a language which describes the structure of a document, not its presentation. The format of the displayed document is up to the browser.
The key feature of a hypetext document is its ability to link to other documents. This link is called an anchor. Documents are referenced by their Uniform Resource Locator (URL).
The WEB is implemented by a set of programs called servers that are responsible for distributing requested documents.
A HTML document is displayed by a program called a browser. The most common browsers are:
A simple, but complete, example.
<TITLE> your title </TITLE>
<H1>the main heading</H1>
The first sentence.
The second sentence
<P>
A new paragraph.
Text can be italic or bold.
Text can be <i>italic</i> or <b>bold</b>
A numbered list example:
<ol> <li> one <li> two <li> three </ol>
An anchor example is:
A good place to start is www.yahoo.com
A good place to start is <a href=http://www.yahoo.com> www.yahoo.com <a>
A URL contains the following fields: a protocol, a host, and a document.
protocol://hostname/document
Some examples are:
http://web.cs.mun.ca/~rod/index.html ftp://garfield.cs.mun.ca/file.txt gopher://cwis.ucs.mun.ca/11/ http://web.cs.mun.ca/cgi-bin/test-cgi
The WEB as currently portrayed is static. It consists of servers distributing fixed documents to browsers. Most servers however have the capabilities to run programs. These programs are called common gateway interfaces (cgi) scripts.
Some of the common uses of these scripts are:
One of the main disadvantages of cgi scripts is that they run on the server. If, instead, the scripts were run on the browser then the capabilites of the WEB could grow dynamically. While there are no production systems with browser-side scripts there are several experimental systems: