XML Introduction - What is XML?

|  | Search W3Schools : |

HOME | HTML | CSS | XML | JAVASCRIPT | ASP | PHP | SQL | MORE... |  | References | Examples | Forum | About

ADVERTISEMENTS XML Certification Download XML editor Custom Programming |  |

Table of contents

XML Basic
XML HOME
XML Introduction
XML How to use
XML Tree
XML Syntax
XML Elements
XML Attributes
XML Validation
XML Validator
XML Viewing
XML CSS
XML XSLT
XML JavaScript
XML Parser
XML DOM
XML to HTML
XML HTTP Request
XML Application
XML Advanced
XML Namespaces
XML CDATA
XML Encoding
XML Server
XML DOM Advanced
XML Don't
XML Technologies
XML in Real Life
XML Editors
XML Summary
Examples/Quiz
XML Examples
XML Quiz
XML Exam

Selected Reading

Web Statistics
Web Glossary
Web Hosting
Web Quality
W3Schools Tutorials
W3Schools Forum
Helping W3Schools

# Introduction to XML

XML was designed to transport and store data.

HTML was designed to display data.

## What You Should Already Know

Before you continue you should have a basic understanding of the following:

- HTML
- JavaScript

If you want to study these subjects first, find the tutorials on our Home page.

## What is XML?

- XML stands for EXtensible Markup Language
- XML is a markup language much like HTML
- XML was designed to carry 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

## The Difference Between XML and HTML

XML is not a replacement for HTML.

XML and HTML were designed with different goals:

- XML was designed to transport and store data, with focus on what data is.
- HTML was designed to display data, with focus on how data looks.

HTML is about displaying information, while XML is about carrying information.

## XML Does not DO Anything

Maybe it is a little hard to understand, but XML does not DO anything. XML was created to structure, store, and transport information.

The following example is a note to Tove from Jani, stored as XML:

    <note>
    <to>Tove</to>
    <from>Jani</from>
    <heading>Reminder</heading>
    <body>Don't forget me this weekend!</body>
    </note>

The note above is quite self descriptive. It has sender and receiver information, it also has a heading and a message body.

But still, this XML document does not DO anything. It is just pure information wrapped in tags. Someone must write a piece of software to send, receive or display it.

## XML is Just Plain Text

XML is nothing special. It is just plain text. Software that can handle plain text can also handle XML.

However, XML-aware applications can handle the XML tags specially. The functional meaning of the tags depends on the nature of the application.

## With XML You Invent Your Own Tags

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.

That is because the XML language has no predefined tags.

The tags used in HTML (and the structure of HTML) are predefined. HTML documents can only use tags defined in the HTML standard (like <p>, <h1>, etc.).

XML allows the author to define his own tags and his own document structure.

## XML is Not a Replacement for HTML

XML is a complement to HTML.

It is important to understand that XML is not a replacement for HTML. In most web applications, XML is used to transport data, while HTML is used to format and display the data.

My best description of XML is this:

XML is a software and hardware independent tool for carrying information.

## XML is a W3C Recommendation

XML became a W3C Recommendation 10. February 1998.

To read more about the XML activities at W3C, please read our W3C Tutorial.

## XML is Everywhere

We have been participating in XML development since its creation. It has been amazing to see how quickly the XML standard has developed, and how quickly a large number of software vendors have adopted the standard.

XML is now as important for the Web as HTML was to the foundation of the Web.

XML is everywhere. It is the most common tool for data transmissions between all sorts of applications, and is becoming more and more popular in the area of storing and describing information.

## Get Your Diploma!

W3Schools' Online Certification Program is the perfect solution for busy professionals who need to balance work, family, and career building.

The HTML Certificate is for developers who want to document their knowledge of HTML, XHTML, and CSS.

The JavaScript Certificate is for developers who want to document their knowledge of JavaScript and the HTML DOM.

The XML Certificate is for developers who want to document their knowledge of XML, XML DOM and XSLT.

The ASP Certificate is for developers who want to document their knowledge of ASP, SQL, and ADO.

The PHP Certificate is for developers who want to document their knowledge of PHP and SQL (MySQL).

WEB HOSTING
Web based charting for ASP.NET
$15 Domain Name Registration Save $20 / year!
Buy UK Domain Names Register Domain Names
Cheap Domain Names Cheap Web Hosting
Best Web Hosting
PHP MySQL Hosting
Top 10 Web Hosting
UK Reseller Hosting
Web Hosting
FREE Web Hosting

WEB BUILDING
Website Templates Flash Templates Website Builder Internet Business Opportunity
Custom Programming
FREE Trial or Demo Web Content Manager Forms,Web Alerts,RSS
Download XML editor
FREE Flash Website
FREE Web Templates

EDUCATION
US Web Design Schools
HTML Certification
JavaScript Certification
XML Certification
PHP Certification
ASP Certification

HOME or Top of Page |  | Printer Friendly
W3Schools is for training only. We do not warrant the correctness of its content. The risk from using it lies entirely with the user. While using this site, you agree to have read and accepted our terms of use and privacy policy. Copyright 1999-2009 by Refsnes Data. All Rights Reserved.