Programming languages and environments

The use of HTML programming languages extend beyond the capabilities of the Web. They are used to write software, process web forms, fetch and display data, and perform all kinds of advanced functions. It is difficult to talk about these languages without getting into too much technical jargon, but here is an attempt. What follows is a brief guide to some of the more common languages in use on the Web today.

CGI (Common Gateway Interface) refers to a specification by which programs can communicate with a Web server. A CGI program, or script, is any program designed to process data that conforms to the CGI specification. The program can be written in any programming language, including C, Perl, and Visual Basic Script (VBScript). In the early days of the Web, CGI scripts were commonly used to process a form on a Web page. Perl is popular with Google, and is also the language of the Movable Type blog platform.

Active Server Pages (ASP): Developed by Microsoft, ASP is a programming environment that processes scripts on a Web server. The programming language VBScript is often used for the scripting. Lightweight programs can be written with this language. Active Server Pages, end in the file extension. Asp. For an example, check out the Databases and Indexes at the University at Albany Libraries.

. NET framework: Also developed by Microsoft, this development framework is a more powerful one than ASP for writing applications for the Web. Programming languages include C + and VB.Net. ASP.Net is a related environment, producing pages with the file extensions. Aspx. The Microsoft site is a good example of a site created with the. NET framework.

PHP: This is another server-based language. It is frequently the language used to write open source (eg, non-profit, community-created) programs found on the Web, including MediaWiki (the software that runs the Wikipedia), and the popular blog software WordPress. While PHP functionality can be installed on Windows servers, it is native to the Linux server environment and commonly used there.

Java / Java Applets: Java is a programming language similar to C + +. Developed by Sun Microsystems, the aim of Java is to create programs that will be platform independent. The Java motto is, "Write once, run anywhere." A perfect Java programs should work equally well on a Windows, Apple, Unix, or Linux servers, and so on, without any additional programming. This goal has yet to be realized. Java can be used to write applications for both Web and non-Web use.
Web-based Java applications are usually in the form of Java servlets. These are small Java programs fetched from within a Web page that can be downloaded from a server and run on a Java-compatible Web browser. A Web page that links to a Java servlet has the file extension. Jsp.

JavaScript is a very popular programming language created by Netscape Communications. Small programs written in this language are embedded within a Web page, or fetched externally from within the page, to enhance the page's functionality. Examples of JavaScript include drop-down menus, image displays, and mouse-over interactions. The drop-down menus on the site of the UCLA Library shown below are a good

XML: XML (Extensible Markup Language) is a mark-up language that enables Web designers to create customized tags to provide functionality not available with HTML alone. XML is a language of the data structure and exchange, and allows developers to separate form from content. With XML, the same content can be formatted for multiple applications. In May 1999, the W3 Consortium announced that HTML 4.0 has been recast as an XML application called XHTML.

AJAX stands for Asynchronous JavaScript and XML. This langauge is used to create interactive Web applications. Its premise is that it sends data to the browser behind the scenes, so that when it is time to view the information, it is already "there." Google Maps is a well-known example of AJAX. A different kind of example can be found with SurfWax LookAhead, an RSS search tool that retrieves feeds as you type your search.

SQL (Structured Query Language): This is a language that Focuses on extracting data from databases. Programmers write statements called queries that retrieve data from the tables in the database. Some Web sites extensively or are created entirely from data stored in database tables. You can often tell that a SQL query has produced data on a page by the presence of a question mark (?) And a record number in the URL, as the example below illustrates.

source http://www.internettutorials.net/www.asp

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Anatomy of a URL in World

This is the format of the URL:

protocol: / / host / path / filename

For example, this is a URL from the site of the U.S. Senate of a live video stream sent by a camera pointed at the U.S. Capitol:

http://www.senate.gov/general/capcam.htm

This is typical of the URL addresses hosted in domains in the United States. The structure of this URL is shown below.

• Protocol: http


• Host computer name: www


• Second-level domain name: Senate


• Top-level domain name: gov


• Directory name: general


• File name: capcam.htm

Note how much information about the content of the file is present in this well-constructed URLs.
Several top-level domains (TLDs) are common in the United States:

com---->commercial enterprise

edu---->educational institutionU.S.

gov---->government entityU.S.

mil---->military entity

net---->network access provder

org---->usually nonprofit organizations

Additional domain names were approved in November 2000 by the Internet Corporation for Assigned Names and Numbers (ICANN):. Biz,. Museum,. Info,. Pro (for professionals). Name (for individuals),. Aero (for the aerospace industry ), and. coop (for cooperatives). ICANN continues to investigate proposals for additional addding domain names. In the Meantime, unconventional domain names have been marketed outside of the system, for example,. Tv for sites that offer content similar to television broadcasts.
In addition, dozens of domain names have been assigned to identify and locate files stored on servers in countries around the world. These are referred to as country codes, and have been standardized by the International Standards Organization as ISO 3166. For example:

ch---->Switzerland

de---->Germany

jp---->Japan

uk---->United Kingdom

As the technology of the Web evolves, URLs have become more complex. This is especially the case when content is retrieved from databases and served onto Web pages.

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Web Terms

Hypertext and links: the motion of the Web

The operation of the Web relies primarily on hypertext as its means of information retrieval. Hypertext is a document containing words that connect to other documents. These words are called links and are selectable by the user. A single hypertext document can contain links to many documents. In the context of the Web, words or graphics may serve as links to other documents, images, video, and sound. Links may or may not follow a logical path, as each connection is created by the author of the source document. Overall, the Web contains a complex virtual web of connections among a Vast number of documents, images, videos, and sounds.

Pages on the Web

The backbone of the World Wide Web are its files, called pages or Web pages, containing information and links to resources - both text and multimedia - throughout the Internet. Web pages can be created by user activity. For example, if you visit a Web search engine and enter keywords on the topic of your choice, a page will be created containing the results of your search. In fact, a growing amount of information found on the Web today is served from databases, creating temporary Web pages "on the fly" in response to user searches

Retrieving doucuments on the Web: The URL and Domain Name System

URL stands for uniform resource locator. The URL specifies the Internet address of a file stored on a host computer, or server, connected to the Internet. Web browsers use the URL to retrieve the file from the server. This file is downloaded to the user's computer, or client, and displayed on the monitor connected to the machine. Because of this relationship between clients and servers, the Web is a client-server network.

Every file on the Internet, no matter what its protocols, has a unique URL. URLs are translated into numeric addresses using the domain name system (dns). The DNS is a worldwide system of servers that stores location pointers to Web sites. The numeric address, called the ip (internet protocol) address, is actually the "real" URL. Since numeric strings are difficult for humans to use, alphneumeric addresses are employed by end users. Once the translation is made by the DNS, the browser can contact the Web server and ask for a specific file located on its site.
For example, 207.46.192.254 is also http://www.microsoft.com/.

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What is the World Wide Web

This tutorial covers the basics of the World Wide Web, with a focus on technical aspects.

World Wide Web is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface. World Wide Web is often abbreviated as the Web or www.

World Wide Web was developed in 1989 by Tim Berners-Lee of the European Particle Physics Laboratory (CERN) in Switzerland. The initial purpose of the Web is to use hypertext network to facilitate communication among its members, which is located in several countries. Word soon spread beyond CERN, and the rapid growth in the number and developers and users occurs. In addition to hypertext, the Web began to include graphics, video, and sound. The use of the Web has reached global proportions and has become a decisive element of human culture in a remarkable short period of time.

In order for the Web can be accessed by anyone, some agreed standards must be followed in the creation and delivery of content. Organization leads efforts to standardize the Web is the World Wide Web (W3C) Consortium. Look at the W3C Consortium Web site to get an idea of its activities. Many technical material because, after all, the Web is a technical phenomenon.

Web Protocols
The simplicity of the Web comes from the fact that many individuals may be contained in the protocol a Web site. Internet protocol that allows a series of rules for communication on the Internet intermachine. Here are some of the protocols that can be experienced on the Web:

• HTTP (HyperText Transfer Protocol): transmits hyptertext over networks. This is the protocol of the Web.
• E-mail (Simple Mail Transport Protocol or SMTP): distributes e-mail messages and attached files to one or more electronic mailboxes.
• FTP (File Transfer Protocol): transfers files between an FTP server and a computer, for example, to download the software.
• VoIP (Voice over Internet Protocol): allows delivery of voice communications over IP networks, for example, phone calls.

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Tutorial Yahoo Messenger (Know Your IP Address)

Please try to send any file, eg an image file to your chat friends in yahoo messenger.

- By the time the file transfer process is in progress, then do this.

1. start - run - type CMD - hit enter
2. then the command prompt on the screen currently open, please type, netstat and hit enter.
3. it will be seen a few IP addresses, which are shown below.
example:

netstat">C: \ Documents and Settings \> netstat
netstat">
netstat">Active Connections

Proto Local Address Foreign Address State
Win06v5 TCP: 1045 localhost: 1046 ESTABLISHED
Win06v5 TCP: 1046 localhost: 1045 ESTABLISHED
Win06v5 TCP: 1047 localhost: 1048 ESTABLISHED
Win06v5 TCP: 1048 localhost: 1047 ESTABLISHED


Then note the address has an IP address like these suffixes. IP numbers: 5101 SYN_SENT

Example: 63.21.55.22: 5101 SYN_SENT

YM uses port 5101 to send the file. so if there is a number with the suffix ip port: 5101, then that's the IP address of your address the other person.

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