WWW – The World Wide Web
WWW is most often called the Web.
What is the WWW?
- WWW stands for the World Wide Web
- The World Wide Web is most often called the Web
- The Web is a network of computers all over the world
- All the computers in the Web can communicate with each other
- All the computers use a communication standard called HTTP
How Does the WWW Work?
- Information is stored in documents called Web pages
- Web pages are files stored on computers called Web servers
- Computers reading the Web pages are called Web clients
- Web clients view the pages with a program called a Web browser
- Popular browsers are Internet Explorer, Chrome, and Firefox
How Does the Browser Fetch the Pages?
- A browser fetches a Web page from a server by a request
- A request is a standard HTTP request containing a page address
- A page address looks like: http://www.someone.com/page.htm
How Does the Browser Display the Pages?
- All Web pages contain instructions on how to be displayed
- The browser displays the page by reading these instructions
- The most common display instructions are called HTML tags
- The HTML tag for a paragraph looks like this: <p>
- A paragraph in HTML is defined like this: <p>This is a paragraph.</p>
Who is Making the Web Standards?
- The Web standards are not made up by Google or Microsoft
- The rule-making body of the Web is the W3C
- W3C stands for the World Wide Web Consortium
- W3C puts together specifications for Web standards
- The most essential Web standards are HTML, CSS and XML
HTML – Hyper Text Markup Language
HTML is the primary language for building/creating web pages.
HTML is an easy-to-learn markup language.
HTML uses markup tags inside angle brackets like <p>), to define the elements of a web page:
<h1>My First Heading</h1>
<p>My first paragraph.</p>
Try it yourself »
Click on the “Try it yourself” button to see how it works
HTML uses start tags and end tags to markup web page elements: In the example above, the <p> tag marks the start of a paragraph, and </p> marks the end of the paragraph.
By using simple HTML tags, web designers can add headers, paragraphs, text, tables, images, lists, programming code, etc, to a web page (HTML document).
Web browsers (IE, Firefox, Chrome, etc) read HTML documents, interpret the HTML tags, and display the proper output (without displaying the HTML tags):
According to the HTML standard, HTML should be used to define the content of web pages.
CSS – Cascading Style Sheets
CSS defines HOW HTML elements are to be displayed.
CSS describes the visual style (appearance, layout, color, fonts) of HTML elements.
CSS was designed to separate document layout from document content (which greatly improved HTML flexibility and reduced HTML complexity).
CSS is easy to learn. You can use HTML element names as selectors, and list the style properties inside curly brackets:
font-family:”Times New Roman”;
Try it yourself »Click on the “Try it yourself” button to see how it works
CSS saves a lot of work!
The CSS definitions are normally stored in external files. This enables a web developer to change the appearance and layout of every page in a web site, just by editing one single file!
If you have ever tried to change the style of all elements in all your HTML pages, you understand how you can save a lot of work by storing the style definitions in an external file.
My First Web Page
This is a paragraph.
Try it yourself »
Click on the “Try it yourself” button to see how it works
- A scripting language is a lightweight programming language
Server-side scripting is about “programming” the behavior of the server (see the Web ASP/PHP chapter).
What is the HTML DOM?
The HTML DOM defines a standard way for accessing and manipulating HTML documents.
The DOM presents an HTML document as a tree-structure:
HTML DOM Tree Example
XML – EXtensible Markup Language
XML is a cross-platform, software and hardware independent tool for storing and transmitting information.
XML Document Example
What is XML?
- XML stands for EXtensible Markup Language
- XML is a markup language much like HTML
- XML was designed to carry and store data, not to display data
- XML tags are not predefined. You must define your own tags
- XML is designed to be self-descriptive
- XML is a W3C Recommendation
XML Doesn’t DO Anything
XML was not designed to DO anything. XML was created to structure, store and carry information.
The XML document example above is a note, to Tove from Jani, written in XML. The note has a heading and a message body. It also has to and from information. But still, this XML document does not DO anything. It is just pure information wrapped in XML tags. Someone must write a piece of software to send, receive or display it:
Don’t forget me this weekend!
XML Tags are NOT Predefined
XML tags are not predefined. You must “invent” your own tags.
The tags used to mark up HTML documents are predefined, the author of HTML documents can only use tags that are defined in the HTML standard (like <p>, <h1>, etc.).
XML allows the author to define his/her own tags and his/her own document structure.
The tags in the example above (like <to> and <from>) are not defined in any XML standard. These tags are “invented” by the author of the XML document.
ASP and PHP – Server-side Scripting
An HTML file can contain HTML tags, text and scripts.
Server-side scripting is about “programming” the behavior of the server. This is called server-side scripting or server scripting.
Normally, when a browser requests an HTML file, the server returns the file. However, if the file contains a server-side script, the script is executed on the server before the file is returned to the browser as plain HTML.
What can Server Scripts Do?
- Dynamically edit, change or add any content to a Web page
- Respond to user queries or data submitted from HTML forms
- Access any data or databases and return the result to a browser
- Customize a Web page to make it more useful for individual users
- Provide security since your server code cannot be viewed from a browser
Important: Because the scripts are executed on the server, the browser that displays the file does not need to support scripting at all!
SQL – Structured Query Language
SQL is the standard language for accessing and manipulating databases.
Common databases are: MySQL, SQL Server, Access, Oracle, Sybase, and DB2.
Knowledge of SQL is invaluable for anyone who wants to store or retrieve data from a database.
What is SQL?
- SQL stands for Structured Query Language
- SQL allows you to access a database
- SQL is an ANSI standard computer language
- SQL can execute queries against a database
- SQL can retrieve data from a database
- SQL can insert new records in a database
- SQL can delete records from a database
- SQL can update records in a database
- SQL is easy to learn
SQL Database Tables
A database usually contains one or more tables. Each table is identified by a name (e.g. “Customers” or “Orders”). Tables contain records (rows) with data.
Below is an example of a table called “Persons”:
The table above contains three records (one for each person) and four columns (LastName, FirstName, Address, and City).
With SQL, we can query a database and have a result set returned.
A query like this:
Gives a result set like this:
Designing a web site needs careful thinking and planning. The most important thing is to “KNOW YOUR AUDIENCE.”
Users are Scanners
A typical visitor will NOT read the entire content of your Web page!
No matter how much useful information you put into a Web page, a visitor will only spend a few seconds scanning it before he/she decide whether to leave or to stay.
Be sure to make your point in the very first sentence of the page! After that, try to keep the user occupied with short paragraphs, and new headers down the page.
Less is More
Keep the paragraphs as short as possible.
Keep the pages as short as possible.
Keep the chapters as short as possible.
Use a lot of space! Pages overloaded with text will kill your audience.
If you have a lot to say, break your information into smaller chunks and place it on different pages!
Create a consistent navigation structure that is used by all the pages in your Web site.
Don’t use hyperlinks inside each paragraph, to send visitors to every page of your Web. This will destroy the feeling of a consistent navigation structure.
If you must use hyperlinks, add them to the bottom of a paragraph, or to the menu.
Sometimes developers are not aware of the fact that some pages take a long time to download.
Most visitors will leave a Web page that takes more than 7 seconds to download.
Test your web pages over a low-speed modem connection. If your pages take a long time to download, consider removing graphic or multimedia content.
Let your Audience Speak!
Feedback is a very good thing!
Your visitors are your “customers”. Often they will give you some valuable hints about what you could have done better.
Provide a simple way to reach you, and you will get a lot of input from people with different skills and knowledge.
Not everyone on the internet has the same monitor as you.
If you design a Web site to be displayed on a monitor with a high resolution, visitors with lower resolution monitors (like 800×600) might have problems reading your pages.
Make sure you test your Web site on different monitors.
Take a look at our browser display statistics to see the trends in monitor development.
What Browsers Do They Use?
Don’t forget to test your Web site on different browsers.
The most popular browsers today are Internet Explorer, Firefox and Google Chrome.
One wise thing to do when designing Web pages is to use correct HTML. Correct coding will help the browsers to display your pages correctly.
Take a look at our browser statistics to see the trends in browser development.
What Plug-Ins Do They Have?
Sound, video clips, or other multimedia content might require the use of separate programs (plug-ins).
Be sure that your visitors have access to the software needed to view them.
What About Disabilities?
Some people have viewing or hearing disabilities.
They might try to read your pages with Braille or speech-based browsers. Always add text alternatives for images and graphic elements.
Web standards make web development easier.
The World Wide Web Consortium (W3C) creates the web standards.
Why Web Standards?
To make internet a better place, for both developers and visitors, it is important that both browsers and Web developers follow the Web standards.
When developers follow the Web standards, the development is simplified, since it is easier for a developer to understand another’s coding.
Using Web standards will ensure that all browsers will display your Web site properly, without time-consuming rewrites.
Tip: Always validate your pages with a validation service. Validation keeps your documents up to the standards, and free of errors.
Accessibility is an important part of the HTML standard.
Web standards make it easier for people with disabilities to use the Web.
Blind people can use programs to read Web pages for them. People with poor eye sight can rearrange and magnify standard Web pages.
W3C – The World Wide Web Consortium
W3C creates and maintains the Web standards.
From Tim Berners-Lee, the inventor of the World Wide Web, director and founder of the World Wide Web consortium:
“The dream behind the Web is of a common information space in which we communicate by sharing information.”
The World Wide Web Consortium (W3C), founded in 1994, is an international consortium dedicated to “lead the web to its full potential”, which it does by developing specifications, guidelines, software, and tools.
- W3C Stands for the World Wide Web Consortium
- W3C was created in October 1994
- W3C was created by Tim Berners-Lee, the inventor of the Web
- W3C is organized as a Member Organization
- W3C is working to Standardize the Web
- W3C creates and maintains WWW Standards
- W3C Standards are called W3C Recommendations
As developers, especially when creating educational Web sites, we can help turn this dream into reality. The most important W3C standards are:
ECMA – European Computer Manufacturers Association
ECMA, founded in 1961, in order to meet the need for standardizing computer languages and input/output codes.
ECMA is not an official standardization institute, but an association of companies that collaborate with other official institutes like the International Organization for Standardization (ISO) and the European Telecommunications Standards Institute (ETSI).
The latest ECMAScript specification is ECMA-262:
Web Page Validator
A validator is a software program that can check your web pages against the web standards.
When using a validator to check HTML, XHTML or CSS documents, the validator returns a list of errors found, according to your chosen standard.
Make sure you make it a habit to validate all your web pages before publishing.
Validate your HTML files with W3C
Input the address of the page you want to validate in the box below:
Validate your CSS files with W3C
Input the address of the css file that you want to validate in the box below:
Validate as: CSS3 CSS2.1 CSS2 CSS1
Validate your XHTML files with W3C
An XHTML document is validated against a Document Type Definition (DTD).
You can read more about XHTML validation in our HTML tutorial.
Input the address of the page you want to validate in the box below:
Validate your XML files with Internet Explorer
Input the address of the page you want to validate in the box below:
Validate your WML files with Internet Explorer
Input the address of the page you want to validate in the box below:
Fast, Powerful, Customizable, and Offline HTML, CSS, Accessibility, SEO, and Link Checking.
- Super-fast offline HTML, CSS, link, and more checking
- Built-in editor lets you easily find and fix problem
- Search engine checking (SEO) to help improve rankings
- Checks for issues that other validators don’t
- Accessibility checking, including WCAG 2.0
- Check everything with just one click or keypress
- Customize the message output to your needs
- Check an entire site with the Batch Wizard
- Easily check the output of dynamic pages
- Prices start at just $69, and a free trial is available
What is the Semantic Web?
The Semantic Web is a web that is able to describe things in a way that computers can understand.
- The Beatles was a popular band from Liverpool.
- John Lennon was a member of the Beatles.
- “Hey Jude” was recorded by the Beatles.
Sentences like the ones above can be understood by people. But how can they be understood by computers?
Statements are built with syntax rules. The syntax of a language defines the rules for building the language statements. But how can syntax become semantic?
This is what the Semantic Web is all about. Describing things in a way that computers applications can understand it.
The Semantic Web is not about links between web pages.
The Semantic Web describes the relationships between things (like A is a part of B and Y is a member of Z) and the properties of things (like size, weight, age, and price)
|“If HTML and the Web made all the online documents look like one huge book, RDF, schema, and inference languages will make all the data in the world look like one huge database”
Tim Berners-Lee, Weaving the Web, 1999
The Resource Description Framework
The RDF (Resource Description Framework) is a language for describing information and resources on the web.
Putting information into RDF files, makes it possible for computer programs (“web spiders”) to search, discover, pick up, collect, analyze and process information from the web.
The Semantic Web uses RDF to describe web resources.
If you want to learn more about RDF, please read our RDF tutorial.
How can it be used?
If information about music, cars, tickets, etc. were stored in RDF files, intelligent web applications could collect information from many different sources, combine information, and present it to users in a meaningful way.
Information like this:
- Car prices from different resellers
- Information about medicines
- Plane schedules
- Spare parts for the industry
- Information about books (price, pages, editor, year)
- Dates of events
- Computer updates
Can it be understood?
The Semantic Web is not a very fast growing technology.
One of the reasons for that is the learning curve. RDF was developed by people with academic background in logic and artificial intelligence. For traditional developers it is not very easy to understand.
One fast growing language for building semantic web applications is RSS. If you want to learn more about RSS, please read our RSS tutorial.
In the following pages of this tutorial we will concentrate on using RDF to discover the potentials of the semantic web.
Buying and selling used cars
Suppose a semantic web system was built to administer the selling and buying of used cars over the Internet.
The system would contain two main applications:
- One for people who wanted to buy a car
- One for people who wanted to put up a car for sale
Let’s call the Internet applications for IBA (I Buy Application), and ISA (I Sell Application).
IBA – The I Buy Application
People who want to buy a car could use an IBA application much like this:
I Buy Application (IBA)
In a “real live” application you would be asked to identify yourself the first time you used it. Your ID would be stored in an RDF file. Your ID would identify you as a person with name, address, email, and ID number.
When you submitted the query, the application would return a list of cars for sale, and the list could be drilled down and sorted by year, price, location and availability. This information would be returned from a web spider continuously searching the web for RDF files.
ISA – The I Sell Application
People who want to sell a car could use an ISA application much like this:
I Sell Application (ISA)
When you submitted the form, the application would ask you for more information and store your ID and the information in an RDF file made available to the web.
The RDF file would contain information like:
Your ID: Name, address, email, ID number.
Your selling item: type, model, picture, price, description.
Behind the scenes
Behind the scenes, the “ISA” application creates an RDF file with a lot of RDF pointers.
It creates an RDF pointer to a file with information about you, an RDF pointer to information about Volvo and Volvo models, an RDF pointer to Volvo dealers and resellers, about parts, about prices, and much more.
An RDF pointer is a pointer (actually an URL) to information about things (like a knowledge database).
The beauty about this is that you don’t have to describe yourself, or the car model. The RDF application will sort it out for you.
Will it ever work?
Chaos? Standards? What do we need? What are we waiting for?
A standard by W3C, by Microsoft, by Google?
RDF is data about data – or metadata. Often RDF files describe other RDF files. Will it ever be possible to link all these RDF files together and build a semantic web?
No one knows, but someone will try.
Will it work all by itself?
I don’t think the semantic web will work all by itself. It will need some help to become a reality.
It is not very likely that you will be able to sell your car just by putting your RDF file on the Internet.
The “ISA” and “IBA” applications above will have to be developed by someone. Someone will have to build a search engine database for all the items, and someone will have to develop a standard for it.
It might be eBay, it might be Microsoft, it might be Google, or someone else. But someone will.
Soon we will see marketplaces based on RDF. And one day you will be able to collect information about almost everything on the web in a standardized RDF format.
It might not be free. You might have to pay for the information, or at least for selling your products.
Publishing information about things on the Internet will be much easier than before. Maybe the RSS language (see our RSS tutorial) will be the solution to some of the problems.
Semantic Web Agents
The semantic web will not be searchable in free text. To search (or access) the semantic web, we will need some software to help us.
To use the semantic web, we will need “Semantic Web Agents” or “Semantic Web Services”. These “Agents” or “Services” will help us to find what we are looking for on the semantic web.
On the semantic web, we might want to look for information about:
- The cheapest airline tickets
- Styling that would fit my car
- Books, DVDs, and CDs
- Weather forecasts
- Time schedules and calendar events
- Stock prices and exchange rates
Semantic Web Security
Can I trust a seller on the semantic web. Can I trust a buyer on the semantic web?
To solve, I will need access to more RDF files:
- Credit card information
- Bank information
- Semantic records
- Social Security information
|Source||Person ID||Person Name||Status|
|US Social Security||11223344||John Smith||born 10-10-1962|
By using RDF files like this, my “Semantic Web Agent” can determine if I can trust the person I am dealing with.
(the “Recorded” information could be supplied by Internet trading companies like eBay, Amazon or the like)
To serve the semantic web, payment methods have to be developed.
Internet accessible “Deposit Accounts” could be a solution to this.
A deposit account is an account that can only receive deposits. It could be made accessible for everyone on the Internet, and everyone could deposit money to your account only knowing your ID (or your email address, much like PayPal).
Using this payment method everyone could publish their bank account number over the Internet and sell their car without any middleman.
OWL – Your Web Thesaurus
- You want to sell a book
- You open your OWL agent
- You entered “Book” in the category
- A new screen is asking you to fill out information about the book
- You fill out the ISBN number written on the book
- You select “used”, and “condition as new”, and hit return
- Your OWL agent automatically fills out the rest
- Author, year, pages, …… all information is now complete
- Your OWL agent has collected all the information you needed to sell the book
- You click on Auction
Your Auction Agent
- Your Auction agent opens.
- You fill out minimum price, and click on “Submit”
- You book becomes available to all the auctions on the Internet
This is an alphabetical list of Web Glossary Terms.
Access (Microsoft Access)
A database system developed by Microsoft. Part of Microsoft Office Professional. Mostly used on low traffic web sites running on the Windows platform.
A web technology for streaming movies from a web server to a web client. Developed by Microsoft.
A programming interface (API) that allows web browsers to download and execute Windows programs. (See also Plug-In)
See Web Address.
Web advertising system provided by Google.
Learn more about AJAX in our AJAX tutorial
In web terms: The starting point or ending point of a hyperlink.
Learn more about links in our HTML tutorial
A mobile phone operating system developed by Android Inc, later purchased by Google.
See FTP Server.
ANSI (American National Standards Institute)
An organization that creates standards for the computer industry. Responsible for the ANSI C standard.
An international standard for the C programming language.
ADO (ActiveX Data Object)
A Microsoft technology that provides data access to any kind of data store.
Learn more about ADO in our ADO tutorial
ADSL (Asymmetric Digital Subscriber Line)
A special type of DSL line where the upload speed is different from the download speed.
See Search Agent / Search Engine
An open source web browser editor from W3C, used to push leading-edge ideas in browser design.
A set of pictures simulating movement when played in series.
A computer program made to discover and destroy all types of computer viruses.
An open source web server. Mostly for Unix, Linux and Solaris platforms.
See web applet.
A computer program to locate files on public FTP servers.
API (Application Programming Interface)
An interface for letting a program communicate with another program. In web terms: An interface for letting web browsers or web servers communicate with other programs. (See also Active-X and Plug-In)
The experimental network tested in the 1970’s which started the development of the Internet.
In web terms: the method used to verify the identity of a user, program or computer on the web.
ASCII (American Standard Code for Information Interchange)
A set of 128 alphanumeric and special control characters used for computer storing and printing of text. Used by HTML when transmitting data over the web.
See the full list of ASCII codes in our HTML Reference
ASF (Advanced Streaming Format)
A multimedia streaming format. Developed by Microsoft for Windows Media.
ASP (Active Server Pages)
A Microsoft technology allowing the insertion of server executable scripts in web pages.
Learn more about ASP in our ASP tutorial
ASX (ASF Streaming Redirector)
An XML format for storing information about ASF files. Developed by Microsoft for Windows Media.
AVI (Audio Video Interleave)
File format for video files. Video compression technology developed by Microsoft.
A (most often graphic) advertisement placed on a web page, which acts as a hyperlink to an advertiser’s web site.
A measure for the speed (amount of data) you can send through an Internet connection. The more bandwidth, the faster the connection.
The number of symbols per second sent over a channel.
BBS (Bulletin Board System)
A web based public system for sharing discussions, files, and announcements.
Data in machine readable form.
Bit (Binary Digit)
The smallest unit of data stored in a computer. A bit can have the value of 0 or 1. A computer uses 8 bits to store one text character.
Blog (Web Log)
A type of website (most often maintained by an individual) with a log of comments (most often personal) comments, meanings, descriptions of events, etc.
A person maintaining or writing content to a web log (blog).
Writing or adding content to a web log (blog).
A format for storing images.
In web terms: A link to a particular web site, stored (bookmarked) by a web user for future use and easy access.
The percentage of web site visitors who view only one web page before they leave (bounce out).
Term to describe a user’s movement across the web, moving from page to page via hyperlinks, using a web browser. (See Web Browser).
BPS (Bits Per Second)
Term to describe the transmission speed for data over the web.
See Web Browser.
Byte (Binary Term)
A computer storage unit containing 8 bits. Each byte can store one text character.
An advanced programming language used for programming advanced computer applications.
C++ (C Plus Plus)
The same as C with added object-oriented functions.
C# (C Sharp)
A Microsoft version of C++ with added Java-like functions.
A term used to describe if it is of importance to use upper or lower case letters.
In web terms: A web browser or web server feature which stores copies of web pages on a computer’s hard disk.
An on-line text-based communication between Internet users.
CGI (Common Gateway Interface)
A set of rules that describes how a CGI program communicates with a web server.
The folder (or directory) on a web server that stores CGI programs.
A small program that handles input and output from a web server. Often CGI programs are used for handling forms input or database queries.
A codec for computer video.
See Web Client.
In web terms: The communication and separation of workload between a web client and a web server.
In web terms: A mouse click on a hyperlink element (such as text or picture) on a web page which creates an event such as taking a visitor to another web page or another part of the same page.
The number of times visitors click on a hyperlink (or advertisement) on a page, as a percentage of the number of times the page has been displayed.
Storing applications and data on the internet (instead of on the user’s computer).
Codec (Compressor / Decompressor)
Common term for the technology used for compressing and decompressing data.
A standard (language and a set of rules) to allow computers to interact in a standard way. Examples are IP, FTP, and HTTP.
Learn more about Communication Protocols in our TCP/IP tutorial
A method of reducing the size (compress) of web documents or graphics for faster delivery via the web.
A computer program that can harm a computer by displaying messages, deleting files, or even destroying the computer’s operating system.
Information from a web server, stored on your computer by your web browser. The purpose of a cookie is to provide information about your visit to the website for use by the server during a later visit.
Web development software for most platforms (Linux, Unix, Solaris and Windows).
CSS (Cascading Style Sheets)
A W3C recommended language for defining style (such as font, size, color, spacing, etc.) for web documents.
Learn more about CSS in our CSS tutorial
Data stored in a computer in such a way that a computer program can easily retrieve and manipulate the data.
Learn more about databases in our SQL tutorial
A computer program (like MS Access, Oracle, and MySQL) for manipulating data in a database.
A database system from IBM. Mostly for Unix and Solaris platforms.
DBA (Data Base Administrator)
The person (or the software) who administers a database. Typical task are: backup, maintenance and implementation.
DHCP (Dynamic Host Configuration Protocol)
An Internet standard protocol that assigns new IP addresses to users as need.
DHTML (Dynamic HTML)
A term commonly to describe HTML content that can change dynamically.
Learn more about DHTML in our DHTML tutorial
In web terms: A connection to Internet via telephone and modem.
DNS (Domain Name Service)
A computer program running on a web server, translating domain names into IP addresses. Learn more about DNS in our Web Hosting tutorial
A web server running DNS.
DOM (Document Object Model)
A programming model for web page objects. (See HTML DOM and XML DOM)
The name that identifies a web site. (like: W3Schools.com)
Learn more about domains in our Web Hosting tutorial
DOS (Disk Operating System)
A general disk based computer operating system (see OS). Originally developed by Microsoft for IBM personal computers. Often used as a shorthand for MS-DOS.
To transfer a file from a remote computer to a local computer. In web terms: to transfer a file from a web server to a web client. (see also Upload).
DSL (Digital Subscriber Line)
An Internet connection over regular telephone lines, but much faster. Speed may vary from 128 kilobit per second, up to 9 megabit per second.
DTD (Document Type Definition)
A set of rules (a language) for defining the legal building blocks of a web document like HTML or XML.
Learn more about DTD in our DTD tutorial
An IP address that changes each time you connect to the Internet. (See DHCP and Static IP).
E-mail (Electronic Mail)
Messages sent from one person to another via the Internet.
The address used for sending e-mails to a person or an organization. Typical format is username@hostname.
A web server dedicated to the task of serving e-mail.
To convert data from its original form to a form that can only be read by someone that can reverse the encryption. The purpose of encryption is to prevent unauthorized reading of the data.
See Web Server Error.
A type of local area network (see LAN).
Software that acts as a security filter that can restrict types of network communication. Most often used between an individual computer (or a LAN) and the Internet.
A vector-based multimedia format developed by Adobe for use on the web.
See HTML Form.
In web terms: The same as Newsgroup.
In web terms: A part of the browser screen displaying a particular content. Frames are often used to display content from different web pages.
Web development software for the Windows platform. Developed by Microsoft.
FTP (File Transfer Protocol)
One of the most common methods for sending files between two computers.
A web server you can logon to, and download files from (or upload files to). Anonymous FTP is a method for downloading files from an FTP server without using a logon account.
A computer program for transferring (and reformatting) data between incompatible applications or networks.
GIF (Graphics Interchange Format)
A compressed format for storing images developed by CompuServe. One of the most common image formats on the Internet.
Same as Gigabyte. 10GB is ten gigabytes.
1024 megabytes. Commonly rounded down to one billion bytes.
In web terms graphics describe pictures (opposite to text).
A display monitor that can display graphics.
A printer that can print graphics.
See Banner Ad.
In web terms: A program helping the browser to display, view, or work with files that the browser cannot handle itself. (See Plug-In).
The number of times a web object (page or picture) has been viewed or downloaded. (See also Page Hits).
The top-level (main) page of a web site. The default page displayed when you visit a web site.
See Web Host.
See Web Hosting.
HTML (Hypertext Markup Language)
HTML is the language of the web. HTML is a set of tags that are used to define the content, layout and the formatting of the web document. Web browsers use the HTML tags to define how to display the text.
Learn more about HTML in our HTML tutorial
A document written in HTML.
HTML DOM (HTML Document Object Model)
A programming interface for HTML documents.
Learn more about HTML DOM in our HTML DOM tutorial
A software program for editing HTML pages. With an HTML editor you can add elements like lists, tables, layout, font size, and colors to a HTML document like using a word processor. An HTML editor will display the page being edited exactly the same way it will be displayed on the web (See WYSIWYG).
A form that passes user input back to the server.
Learn more about HTML forms in our HTML tutorial
The same as an HTML Document.
Code to identify the different parts of a document so that a web browser will know how to display it.
Learn more about HTML tags our HTML tutorial
HTTP (Hyper Text Transfer Protocol)
The standard set of rules for sending text files across the Internet. It requires an HTTP client program at one end, and an HTTP server program at the other end.
A computer program that requests a service from a web server.
A computer program providing services from a web server.
HTTPS (Hyper Text Transfer Protocol Secure)
Same as HTTP but provides secure Internet communication using SSL. (see also SSL)
A pointer to another document. Most often a pointer to another web page. A hyperlink is a synonym for a hotlink or a link, and sometimes called a hypertext connection to another document or web page.
An extension to hypertext to include graphics and audio.
Hypertext is text that is cross-linked to other documents in such a way that the reader can read related documents by clicking on a highlighted word or symbol. (see also hyperlink)
IAB (Internet Architecture Board)
A council that makes decisions about Internet standards. (See also W3C).
IE (Internet Explorer)
See Internet Explorer.
IETF (Internet Engineering Task Force)
A subgroup of IAB that focuses on solving technical problems on the Internet.
IIS (Internet Information Server)
A web server for Windows operating systems. Developed by Microsoft.
IMAP (Internet Message Access Protocol)
A standard communication protocol for retrieving e-mails from an e-mail server. IMAP is much like POP but more advanced.
Learn more about IMAP in our TCP/IP tutorial
A codec for computer video developed by Intel.
A world wide network connecting millions of computers. (See also WWW)
See Web Browser.
A browser by Microsoft. The most commonly used browser today.
Learn more about browsers in our browser section
See Web Server
A private (closed) Internet, running inside a LAN (Local Area Network).
IP (Internet Protocol)
IP Address (Internet Protocol Address)
A unique number identifying every computer on the Internet (like 18.104.22.168)
IP Number (Internet Protocol Number)
Same as an IP address.
See TCP/IP Packet.
IRC (Internet Relay Chat)
An Internet system that enables users to take part in on-line discussions.
A computer program that enables a user to connect to IRC.
An Internet server dedicated to the task of serving IRC connections.
ISAPI (Internet Server API)
Application Programming Interface (See API) for Internet Information Server (See IIS).
ISDN (Integrated Services Digital Network)
A telecommunication standard that uses digital transmission to support data communications over regular telephone lines.
ISP (Internet Service Provider)
Someone that provides access to the Internet and web hosting.
A programming language developed by SUN. Mostly for programming web servers and web applets.
See Web Applet.
The most popular scripting language on the internet, developed by Netscape.
JPEG (Joint Photographic Expert Group)
The organization that promotes the JPG and JPEG graphic formats for storing compressed images.
JPEG and JPG
Graphic formats for storing compressed images.
JSP (Java Server Pages)
A Java based technology allowing the insertion of server executable scripts in web pages. Mostly used on Linux, Unix and Solaris platforms.
Same as kilobyte 10K is ten kilobytes..
Same as kilobyte 10KB is ten kilobytes..
In web terms: A word used by a search engine to search for relevant web information.
In database terms: A word (or index) used to identify a database record.
1024 bytes. Often called 1K, and rounded down to 1000 bytes.
LAN (Local Area Network)
A network between computers in a local area (like inside a building), usually connected via local cables. See also WAN.
The same as a hyperlink.
Open source computer operating system based on Unix. Mostly used on servers and web servers.
In web terms: the same as e-mail.
See e-mail server.
Same as Megabyte. 10MB is ten megabytes.
1024 kilobytes. Commonly rounded down to one million bytes.
Data that describes other data. (See also Meta Tags).
The method of searching for meta data in documents.
Tags inserted into documents to describe the document.
Learn more about meta tags in our HTML tutorial
MIDI (Musical Instrument Digital Interface)
A standard protocol for communication between computers and musical instruments.
Learn more about MIDI in our Media tutorial
MIME (Multipurpose Internet Mail Extensions)
An Internet standard for defining document types. MIME type examples: text/plain, text/html, image/gif, image/jpg.
Learn more about MIME types in our Media tutorial
Document types defined by MIME.
Hardware equipment to connect a computer to a telephone network Typically used to connect to the Internet via a telephone line.
The first commonly available web browser. Mosaic was released in 1993 and started the popularity of the web.
A codec for computer video developed by Apple. Common file extension for QuickTime multimedia files.
MP3 (MPEG-1 Audio Layer-3)
An audio compression format specially designed for easy download over the Internet.
An file containing audio compressed with MP3. Most often a music track.
MPEG (Moving Picture Expert Group)
An ISO standard codec for computer audio and video.
Common file extension for MPEG files.
MS-DOS (Microsoft Disk Operating System)
A general disk based computer operating system (See OS). Originally developed by Microsoft for IBM computers, then developed by Microsoft as a basis for the first versions of Windows.
In web terms: A presentation combining text with pictures, video, or sound.
Free open source database software often used on the web.
NetBEUI (Net Bios Extended User Interface)
An enhanced version of NetBIOS.
NetBIOS (Network Basic Input Output System)
An application programming interface (API) with functions for local-area networks (LAN). Used by DOS and Windows.
In web terms: The same as Browse.
The browser from the company Netscape. The most popular browser for many years. Today IE has the lead.
Learn more about browsers in our browser section
An on-line discussion group (a section on a news server) dedicated to a particular subject of interest.
A computer program that enables you to read (and post messages) from an Internet newsgroup.
An Internet server dedicated to the task of serving Internet newsgroups.
In web terms: A computer connected to the Internet, most often used to describe a web server.
The browser from the company Opera.
Learn more about browsers in our browser section
OS (Operating System)
The software that manages the basic operating of a computer.
See TCP/IP Packet.
The number of times a web page has been visited by a user.
The same as Page Hits.
The same as Page Hits.
PDF (Portable Document Format)
A document file format developed by Adobe. Most often used for text documents.
Perl (Practical Extraction and Reporting Language)
A scripting language for web servers. Most often used on Unix servers.
PHP (PHP: Hypertext Preprocessor)
A technology allowing the insertion of server executable scripts in web pages. Mostly for Unix, Linux and Solaris platforms.
Learn more about PHP in our PHP tutorial.
A method used to check the communication between two computers. A “ping” is sent to a remote computer to see if it responds.
In web terms: The computer’s operating system like Windows, Linux, or OS X.
An application built into another application. In web terms: A program built in (or added) to a web browser to handle a special type of data like e-mail, sound, or movie files. (See also ActiveX)
PNG (Portable Network Graphics)
A format for encoding a picture pixel by pixel and sending it over the web. A W3C recommendation for replacing GIF.
POP (Post Office Protocol)
A standard communication protocol for retrieving e-mails from an e-mail server. (See also IMAP).
Learn more about POP and IMAP in our TCP/IP tutorial
A number that identifies a computer IO (input/output) channel. In web terms: A number that identifies the I/O channel used by an Internet application (A web server normally uses port 80).
See Communication Protocol.
PPP (Point to Point Protocol)
A communication protocol used for direct connection between two computers.
An Internet server dedicated to improve Internet performance.
A multimedia file format created by Apple.
Learn more about QuickTime in our Media tutorial
RAID (Redundant Array of Independent Disks)
A standard for connecting multiple disks to the same server for higher security, speed and performance. Often used on web servers.
RDF (Resource Description Framework)
A framework for constructing languages for describing web resources.
Learn more about RDF in our RDF tutorial
A common multimedia audio format created by Real Networks.
Learn more about Real Audio in our Media tutorial
A common multimedia video format created by Real Networks.
Learn more about Real Video in our Media tutorial
In web terms: The action when a web page automatically forwards (redirects) the user to another web page.
RGB (Red Green Blue)
The combination of the three primary colors that can represent a full color spectrum.
Learn more about RGB in our HTML tutorial
See Web Robot.
A hardware (or software) system that directs (routes) data transfer to different computers in a network.
See XML Schema.
A collection of statements written in a Scripting Language.
Writing a script.
Same as Search Engine.
Computer program used to search and catalog (index) the millions of pages of available information on the web. Common search engines are Google and AltaVista.
A web of data with a meaning in the sense that computer programs can know enough about the data to process it.
See Web Server.
See Web Server Errors.
Software that you can try free of charge, and pay a fee to continue to use legally.
A format (technology) developed by Adobe for embedding multimedia content in web pages.
SGML (Standard Generalized Markup Language)
An international standard for markup languages. The basis for HTML and XML.
SMIL (Synchronized Multimedia Integration Language)
A W3C recommended language for creating multimedia presentations.
SMTP (Simple Mail Transfer Protocol)
A standard communication protocol for sending e-mail messages between computers.
Learn more about SMTP in our TCP/IP tutorial
SOAP (Simple Object Access Protocol)
A standard protocol for letting applications communicate with each other using XML.
Learn more about SOAP in our SOAP tutorial
Computer operating system from SUN.
In web terms: The action of sending multiple unwelcome messages to a newsgroup or mailing list.
See Web Spider.
Addressing a web page or an e-mail with a false referrer. Like sending an e-mail from a false address.
Computer software hidden in a computer with the purpose of collecting information about the use of the computer.
SQL (Structured Query Language)
An ANSI standard computer language for accessing and manipulating databases.
Learn more about SQL in our SQL tutorial.
A database system from Microsoft. Mostly used on high traffic web sites running on the Windows platform.
SSI (Server Side Include)
A type of HTML comment inserted into a web page to instruct the web server to generate dynamic content. The most common use is to include standard header or footer for the page.
SSL (Secure Socket Layer)
Software to secure and protect web site communication using encrypted transmission of data.
Static IP (address)
An IP address that is the same each time connect to the Internet. (See also Dynamic IP).
A method of sending audio and video files over the Internet in such a way that the user can view the file while it is being transferred.
The format used for files being streamed over the Internet. (See Windows Media, Real Video and QuickTime).
SVG (Scalable Vector Graphics)
A W3C recommended language for defining graphics in XML.
Learn more about SVG in our SVG tutorial
In web terms: Notifications or commands written into a web document. (See HTML Tags)
TCP (Transmission Control Protocol)
TCP/IP (Transmission Control Protocol / Internet Protocol)
A collection of Internet communication protocols between two computers. The TCP protocol is responsible for an error free connection between two computers, while the IP protocol is responsible for the data packets sent over the network.
Learn more about TCP/IP in our TCP/IP tutorial
See IP Address.
A “packet” of data sent over a TCP/IP network. (data sent over the Internet is broken down into small “packets” from 40 to 32000 bytes long).
Computer program hidden in another computer program with the purpose of destroying software or collecting information about the use of the computer.
UDDI (Universal Description Discovery and Integration)
A platform-independent framework for describing services, discovering businesses, and integrating business services using the Internet.
Learn more about UDDI in our WSDL tutorial
Computer operating system, developed by Bell Laboratories. Mostly used for servers and web servers.
To uncompress a ZIPPED file. See ZIP.
To transfer a file from a local computer to a remote computer. In web terms: to transfer a file from a web client to a web server. (see also Download).
URI (Uniform Resource Identifier)
Term used to identify resources on the internet. URL is one type of an URI.
URL (Uniform Resource Locator)
A web address. The standard way to address web documents (pages) on the Internet (like: http://www.w3schools.com/)
A world wide news system accessible over the Internet. (See Newsgroups)
The same as a Web Browser.
VB (Visual Basic)
See Visual Basic.
A scripting language from Microsoft. VBScript is the default scripting language in ASP. Can also be used to program Internet Explorer.
Learn more about VBScript in our VBScript tutorial.
Same as Computer Virus.
In web terms: A visit to a web site. Commonly used to describe the activity for one visitor of a web site.
In web terms: A visitor of a web site. Commonly used to describe a person visiting (viewing) a web site.
A programming language from Microsoft.
VPN (Virtual Private Network)
A private network between two remote sites, over a secure encrypted virtual Internet connection (a tunnel).
VRML (Virtual Reality Modeling Language)
A programming language to allow 3D effects to be added to HTML documents.
W3C (World Wide Web Consortium)
The organization responsible for managing standards for the WWW.
Learn more about W3C in our W3C tutorial
WAN (Wide Area Network)
Computers connected together in a wide network, larger than a LAN, usually connected via phone lines. See also LAN.
WAP (Wireless Application Protocol)
An old standard for information services on wireless terminals like digital mobile phones.
The same as an URL or URI. See URL.
A program that can be downloaded over the web and run on the user’s computer. Most often written in Java.
A software program used to access web pages. Sometimes the same as a Web Browser, but often used as a broader term.
A software program used to display web pages.
Learn more about browsers in our Browser section
A document formatted for distribution over the web. Most often a web document is formatted in a markup language like HTML or XML.
See Web Server Error.
See HTML Form.
A web server that “hosts” web services like providing web site space to companies or individuals.
The action of providing web host services.
A document (normally an HTML file) designed to be distributed over the Web.
See Web Spider.
A server is a computer that delivers services or information to other computers. In web terms: A server that delivers web content to web browsers.
Web Server Error
A message from a web server indicating an error. The most common web server error is “404 File Not Found”.
Learn more about web server error messages in our HTML tutorial
Software components and applications running on web servers. The server provides these services to other computers, browsers or individuals, using standard communication protocols.
A collection of related web pages belonging to a company or an individual.
A computer program that searches the Internet for web pages. Common web spiders are the one used by search engines like Google to index the web. Web spiders are also called web robots or wanderers.
See Web Spider.
A character used to substitute any character(s). Most often used as an asterisk (*) in search tools.
Windows 2000, Windows NT, Windows 95/98, Windows XP
Computer operating systems from Microsoft.
Audio and video formats for the Internet, developed by Microsoft. (See ASF, ASX, WMA and WMF).
Learn more about Windows Media in our Media tutorial
A computer program for compressing and decompressing files. See ZIP.
Audio file format for the Internet, developed by Microsoft. (See also WMV).
Learn more about media formats in our Media tutorial.
Video file format for the Internet, developed by Microsoft. (See also WMA).
Learn more about media formats in our Media tutorial
WML (Wireless Markup Language)
An older standard for information services on wireless terminals like digital mobile phones, inherited from HTML, but based on XML, and much stricter than HTML.
Scripting language (programming language) for WML.
A computer virus that can make copies of itself and spread to other computers over the Internet.
WSDL (Web Services Description Language)
An XML-based language for describing Web services and how to access them.
Learn more about WSDL in our WSDL tutorial
WWW (World Wide Web)
A global network of computers using the internet to exchange web documents. (See also Internet)
The same as a Web Server.
WYSIWYG (What You See Is What You Get)
In Web terms: To display a web page being edited exactly the same way it will be displayed on the web.
An alternative version of HTML Forms, based on XML and XHTML. Differs from HTML forms by separating data definition and data display. Providing richer and more device independent user input.
XHTML (Extensible Hypertext Markup Language)
HTML reformulated as XML. Developed by W3C.
Learn more about XHTML in our XHTML tutorial
XPath is a set of syntax rules (language) for defining parts of an XML document. XPath is a major part of the W3C XSL standard.
Learn more about XPath in our XPath tutorial
XQuery is a set of syntax rules (language) for extracting information from XML documents. XQuery builds on XPath. XQuery is developed by W3C.
Learn more about XQuery in our XQuery tutorial
XML (Extensible Markup Language)
A simplified version of SGML especially designed for web documents, developed by the W3C.
Learn more about XML in our XML tutorial
A document written in XML.
Learn more about XML in our XML tutorial
XML DOM (XML Document Object Model)
A programming interface for XML documents developed by W3C.
Learn more about XML DOM in our XML DOM tutorial
Learn more about XMLHttp in our AJAX tutorial
A document that describes, in a formal way, the syntax elements and parameters of a web language. Designed by W3C to replace DTD.
Learn more about Schema in our XML Schema tutorial
XSD (XML Schema Definition)
The same as XML Schema.
XSL (Extensible Stylesheet Language)
A suite of XML languages developed by W3C, including XSLT, XSL-FO and XPath.
Learn more about XSL in our XSL tutorial
XSL-FO (XSL Formatting Objects)
An XML language for formatting XML documents. A part of XSL developed by W3C.
Learn more about XSL-FO in our XSL-FO tutorial
XSLT (XSL Transformations)
An XML language for transforming XML documents. A part of XSL developed by W3C.
Learn more about XSLT in our XSLT tutorial
A compressing format for computer files. Commonly used for compressing files before downloading over the Internet. ZIP files can be compressed (ZIPPED) and decompressed (UNZIPPED) using a computer program like WINZIP.
Have you ever used a search engine? Do you wonder how to get listed? This page will help you to get listed in the most popular search engines.
SEO – Search Engine Optimization
Search engine optimization (SEO) is the process of improving the ranking (visibility) of a website in search engines. The higher (or more frequently) a web site is displayed in a search engine list (like Google), the more visitors it is expected to receive.
SEO considers how search engines work, what people search for, and which search terms (words) are typed. Optimizing a website may involve editing the content to increase its relevance to specific keywords. Promoting a site to increase the number of links, is another SEO tactic.
Effective search engine optimization may require changes to the HTML source code of a site and to the site content. SEO tactics should be incorporated into the website development and especially into the menus and navigation structure.
Another class of techniques, known as black hat SEO or spamdexing, uses methods such as link farms, keyword stuffing and article spinning that degrade both the relevance of search results and the quality of user-experience with search engines. Search engines look for sites that employ these techniques in order to remove them from their indices.
Submit Your Site to Search Engines
Web search engines (like Google) automatically add new web sites to their search index every time they crawl the web.
If your web site is new and unknown, it may take some time before your site is “discovered”.
Luckily most search engines invites you to submit your site: *
Open Directory: http://www.dmoz.org/help/submit.html
Normally you will have to enter the full URL of your site including the http:// prefix.
When you submit your site to a search engine, you only need to specify the top-level (home) page. You do not need to submit each page. The search engine will find the rest based on your links (keep your navigation menus tidy).
Sometimes you can also add keywords that describe the page, but don’t expect these to affect how your site is ranked or listed.
Search engines indexes are updated on a regular basis. Changes to your site will be updated over time (monthly) and dead pages and links will disappear.
* Not all submitted URLs will be added, and you cannot predict or guarantee when or if your site will appear in a search result.