Lecture-1 : Hyper Text Markup Language (HTML)

Introduction


Internet today has become one of the most the sought medium for the exchange of information, whether it is simple chat, E-mail, file transfer, video conferencing or any other commercial application like online ticketing, education, business and research.

Internet is made up of millions of computers networked together worldwide. Networking of these computers make it possible for exchange of information from one system to another. Another terminology related to internet is the word “world wide web” (www), these words are sometime used synony mously but in fact they are different. Whereas internet is network of networks, www is the collection of linked pages called web documents stored on web servers connected to the internet. These pages are written in a special language called Hypertext markup Language.


History of Hypertext Markup Language



HTML is the simple and powerful language used to describe web pages, and is still used as the main interface language to the web. History of HTML goes as described below:

ARPANET was created in 1969, the same year Charles Goldfarb, Edward Mosher, and Raymond Loriewas invented the Generalized Markup Language (GML) to facilitate text management in large information systems. GML was based on the work of Rice and Tunnicliffe with tagging schemes, and added a formal document structure, so that any computer program could automatically process and format the individual parts of the document.

In 1980, the American National Standards Institute (ANSI) committee built on GML and published a working draft of Standard GML, or SGML. The final standard was published with a working SGML system developed by Anders Berglund, then of the European Particle Physics Laboratory (CERN).

A few years later another scientist at CERN, Tim Berners-Lee, invented the HyperText Markup Language (HTML) to define the structure of web pages. Tim never planned HTML to be more than a structure into which a wide range of multi-media documents would be fitted, but it was designed well enough that it came to be used to present a wide range of content itself. The main structure of modern HTML was agreed at a meeting at the first WWW Conference held the week of 25 May, 1994, including the incorporation of tables, graphics, and mathematics symbols, as would be expected for a language then aimed at academic work.

HTML is designed to be as simple as possible. Each command consists of an opening tag in angle brackets, like , and a closing tag with an added slash, like . Some of the most common commands are listed below, together with the result displayed when the HTML is read by a web browser.

Every web page is written in HTML, which is text based, so it's easily and quickly communicated across the Internet. On most browsers you can view the HTML for any web page you visit, by selecting "View Source" from the browser toolbar, or from a pop-up menu appearing when you right-click on a particular frame. When you are finished viewing the web page source you can close that window without affecting any of the pages you are viewing.

Dan Connolly, Jon Bosak, and others at the W3C have also developed a successor to SGML called the Extensible Markup Language (XML), which provides the structure to enable design of a range of languages like HTML for various purposes, and is in wide and increasing use.

HTML is not case sensitive, this means HTML tags can written both lower and upper case letters. Tables, tags can be used anywhere in the web document, because it does not affect the appearance of the document. The web documents are saved with the extension .HTM or .HTML, and finally the web documents are written in notepad or any editor.

HTML Editor


To create the source do, you need an HTML Editor. There are several editors used today. The Most often used are :-

Notepad (Windows OS)
You can use Notepad to create HTML document. When saving the file you have to specify a .html or .htm file name extension

Microsoft FrontPage
This is a comprehensive tool that can be used to create, design and edit Web Pages. You can add text, images, tables and other HTML elements to the page
Once you have created the inference, the FrontPage Editor creates the required HTML code

Other HTML editors are given below:

• TextEdit (Mac OS)
• gedit (Linux OS)

Here are some other free text editors that have more features:

• Notepad++ (Windows OS)
• TextWrangler (Mac OS)
• jEdit (Windows OS, Mac OS, and Linux OS)

For more professional-level, commercial integrated development environments (IDEs), try one of the following:

• Adobe Dreamweaver (Windows OS and Mac OS)
• Panic Software’s Coda (Mac OS)

If you use Notepad, select Format→WordWrap. This option allows long lines to be wrapped within the application window, making it easier to edit.

Web Browser/ Viewing the HTML Documents


HTML documents can be viewed with the help of software called web browser. A web browser interprets the HTML documents, formats it as per the formatting instructions called tags provided in te document, and displays it in the browser's document window on the computer screen.

It can also be defined as one of the many software applications that function as the interface between a user and the Internet. The browser not only sends messages to web servers to retrieve your page request, but also renders the HTML code once it arrives. Some of the commonly used browsers are as follows:

AOL Browser
Flock
Green Browser
Internet Explorer
K-Melon
Maxthon
Mozilla Firefox
Opera
Apple Safari
Netscape Navigator
Google Chrome