Web Programming : Building Internet Applications Chris Bates CSE :

Introduction: WWW Difference between WWW & Internet HTML XML Difference between HTML and XML MIME

World Wide Web The WWW incorporates all of the Internet services -retrieve documents -view images -animation -Video -listen to sound file -speak and hear voice -view programs that run on practically any software in the world, -providing your computer has the hardware and software to do these things.

The Difference Between Internet & WWW The Internet is a massive network of networks, a networking infrastructure. It connects millions of computers together globally, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet. Information that travels over the Internet does so via a variety of languages known as protocols. The World Wide Web, or simply Web, is a way of accessing information over the medium of the Internet. It is an information-sharing model that is built on top of the Internet. The Web uses the HTTP protocol, only one of the languages spoken over the Internet, to transmit data. Web services, which use HTTP to allow applications to communicate in order to exchange business logic, use the the Web to share information. The Web also utilizes browsers, such as Internet Explorer or Netscape , to access Web documents called Web pages that are linked to each other via hyperlinks. Web documents also contain graphics, sounds, text and video.

What is HTML Stands for "Hyper-Text Markup Language." This is the language that Web pages are written in. Also known as hypertext documents, Web pages must conform to the rules of HTML in order to be displayed correctly in a Web browser. The HTML syntax is based on a list of tags that describe the page's format and what is displayed on the Web page. The current version of HTML is HTML4.0. However, both Internet Explorer and Netscape implement some features differently and provide non-standard extensions.

What is XML XML stands for EXtensible Markup Language It is a markup language much like HTML It was designed to describe data XML tags are not predefined. You must define your own tags It uses a Document Type Definition (DTD) or an XML Schema to describe the data It with a DTD or XML Schema is designed to be self-descriptive

Difference between XML and HTML The main XML was designed to carry data. XML is not a replacement for HTML. XML and HTML were designed with different goals: XML was designed to describe data and to focus on what data is. HTML was designed to display data and to focus on how data looks. HTML is about displaying information, while XML is about describing information.

What is MIME Multipurpose Internet Mail Extensions, a specification for formatting non-ASCII messages so that they can be sent over the Internet. Many e-mail clients now support MIME, which enables them to send and receive graphics, audio, and video files via the internet mail system. In addition, MIME supports messages in character sets other than ASCII. There are many predefined MIME types, such as GIF graphics files and Post Script files. It is also possible to define your own MIME types.

Web Development Tools many high-level tools exist for creating Web pages e.g., Microsoft FrontPage, Netscape Composer, Adobe PageMill, Macromedia DreamWeaver, HotDog, … also, many applications have "save to HTML" options (e.g., Word) for most users who want to develop basic, static Web pages, these are fine assembly language vs. high-level language analogy so, why are we learning low-level HTML using a basic text editor? may want low-level control may care about size/readability of pages may want to "steal" page components and integrate into existing pages may want dynamic features such as scripts or applets