Index

1.4 Data Type and Web Page

Session 1 WWW Elementary

1.4.1 Data Type Supported by Internet

Internet is by virtue a packet switch transmission network system. Some older format data types are not supported by internet, e.g. the native format of Adobe Illustrator .ai format v.7 or earlier cannot be transmitted via internet. Now almost all data formats compile with the internet transmission standard.

1.4.2 Data Type for World Wide Web

1.4.2.1 Html & Xtml-

The Web is one of the services that runs on the Internet. It is a collection of textual documents and other resources, linked by hyperlinks and URLs, transmitted by web browsers and web servers. In short, the Web can be thought of as an application "running" on the Internet. The documents are usually in Html or Xtml format.

1.4.2.3 Scripting Language- php, pearl, java script

In addition, some scripting language like java or php embedded into the Html or Xtml web page may be interpreted and viewed by the web browser viewed. (PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. For this purpose, PHP code is embedded into the HTML source document and interpreted by a web server with a PHP processor module, which generates the web page document.).

1.4.2.4 Other Formats- eg. image, drawing, pdf, flash, multimedia.

Viewing other formats on the www is also possible with various plug-in, which is a set of software components that adds specific abilities to a larger software application (the brower in our example).

1.4.3 Implementation of WWW

Berners-Lee's breakthrough was to marry hypertext to the Internet. He developed three essential technologies:

a system of globally unique identifiers for resources on the Web and elsewhere, the Universal Document Identifier (UDI), later known as Uniform Resource Locator (URL) and Uniform Resource Identifier (URI);
the publishing language HyperText Markup Language (HTML);
the Hypertext Transfer Protocol (HTTP).

1.4.3.1 URL

URL, also named as hyper link, can be resolved into ip address using the globally distributed database known as the Domain Name System (DNS). The browser then requests the resource by sending an HTTP request across the Internet to the computer at that particular address. It makes the request to a particular application port, eg. port 80 for email delivery, in the underlying Internet Protocol Suite so that the computer receiving the request can distinguish an HTTP request from other network protocols it may be servicing.

eg.

<http://en.wikipedia.org/wiki/World_Wide_Web >
<mailto:hhcc@um-gallery.net>

1.4.3.2 Html

Hypertext Markup Language (HTML) is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages. HTML is written in the form of HTML elements consisting of tags, enclosed in angle brackets (like <html>), within the web page content. HTML tags normally come in pairs like <h1> and </h1>. The first tag in a pair is the start tag, the second tag is the end tag (they are also called opening tags and closing tags). In between these tags web designers can add text, tables, images, etc.

HTML
(HyperText Markup Language)
Filename extension	.html, .htm
Internet media type	text/html
Type code	TEXT
Uniform Type Identifier	public.html
Developed by	World Wide Web Consortium & WHATWG
Type of format	Markup language
Extended from	SGML
Extended to	XHTML
Standard(s)	ISO/IEC 15445 W3C HTML 4.01 W3C HTML5 (draft)

1.4.3.3 Http

The Hypertext Transfer Protocol (HTTP) is a networking protocol for distributed, collaborative, hypermedia information systems. The standards development of HTTP (now v.1.1, 1999) has been coordinated by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C).