Wednesday, April 20, 2011

The internet, The web, and Electronic Commerce

URL

( Uniform Resource Locator) The address that defines the route to a file on an Internet server (Web server, FTP server, mail server, etc.). URLs are typed into a Web browser to access Web pages and files, and URLs are embedded within the pages themselves as hypertext links. The URL contains the protocol prefix, port number, domain name, subdirectory names and file name. If a port number is not stated in the address, port 80 is used as the default for HTTP traffic.

HTML














HyperText Markup Language, is the predominant markup language for web pages. HTML is the basic building-blocks of webpages.

HTML is written in the form of HTML elements consisting of tags, enclosed in angle brackets (like ), within the web page content. HTML tags normally come in pairs like

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.

Javascript














A popular scripting language that is widely supported in Web browsers and other Web tools. It adds interactive functions to HTML pages, which are otherwise static, since HTML is a display language, not a programming language. JavaScript is easier to use than Java, but not as powerful and deals mainly with the elements on the Web page. On the client, JavaScript is maintained as source code embedded into an HTML page. On the server, it is compiled into bytecode (intermediate language), similar to Java programs.

Applets


A small application, such as a utility program or limited-function spreadsheet or word processor. Java programs that are run from the browser are always known as applets. See midlet, crapplet and Java applet.

Blogs

A blog (a blend of the term web log)[1] is a type of website or part of a website. Blogs are usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video. Entries are commonly displayed in reverse-chronological order. Blog can also be used as a verb, meaning to maintain or add content to a blog.

Wikis

A wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor.Wikis are typically powered by wiki software and are often used to create collaborative works. Examples include community websites, corporate intranets, knowledge management systems, and note services. The software can also be used for personal notetaking.

FTP

Stands for "File Transfer Protocol." It is a common method of transferring files via the Internet from one computer to another. Some common FTP programs are "Fetch" for the Mac, and "WS_FTP" for Windows. However, you can also use a Web browser like Netscape or Internet Explorer to access FTP servers. To do this, you need to type the URL of the server into the location field of the browser. For example: "ftp://ftp.servername.com/" will give you a listing of all the directories of the FTP server, "ftp://ftp.servername.com/directory/" will give you a listing of all the files available in that directory, and "ftp://ftp.servername.com/directory/filename" will download the actual file to your computer. Many FTP servers are "anonymous FTP" servers which means you can log in with the user name "anonymous" and your e-mail address as the password. Other FTP servers require a specific login in order to access the files.

Plug-in

A plug-in (or plugin) is a set of software components that adds specific abilities to a larger software application. If supported, plug-ins enable customizing the functionality of an application. For example, plug-ins are commonly used in web browsers to play video, scan for viruses, and display new file types. Well-known plug-ins examples include Adobe Flash Player and QuickTime.Add-on is often considered the general term comprising snap-ins, plug-ins, extensions, and themes

Filters

To select data. Filters use patterns (masks) against which all data are compared and only matching data are "passed through," hence the concept of a filter. For example, e-mail clients and servers can look for messages with text patterns that are recognized as spam and delete them. An e-mail client can be set up to filter messages and store them in separate mailboxes as a way of organizing the mail, or it can be set to alert the user when a certain type of message arrives. See Bayesian filtering and spam filter.

To change data. In this usage of the term, the concept of a filter (a pass-through device) is less obvious, but nevertheless widely used. For example, a sort routine changes the sequence of data. A conversion routine (import or export filter) changes one type of data, text or graphics format into another. See image filter and parse.

Internet security suite

A suite of utilities for maintaining the security of a Windows PC. it includes more than a dozen utilities such as antivirus, personal firewall, spam blocker and popup blocker.

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