XML Basic Tutorial

XML is designed to describe data, with a focus on the content of the data.

HTML is designed to display data, with a focus on the appearance of the data.

Basic knowledge that should be mastered:

Before you continue learning, you need to have a basic understanding of the following knowledge:

  • HTML / XHTML
  • JavaScript or VBScript

If you want to learn these projects first, please visit our Home Access these tutorials.

What is XML?

  • What is XML?Extensible Markup Language（EXtensible Markup Language）
  • XML is amarkup language, very similar to HTML
  • XML is designed todescribe data
  • XML tags are not predefined. You need toself-defined tags.
  • XML usesFile Type Declaration（DTD）or XML Schema to describe data.
  • XML with DTD or XML Schema is designed to beSelf-descriptive.
  • XML is a W3C standard

XML is a W3C standard

The Extensible Markup Language was established as a W3C standard on February 10, 1998.

You can find ourW3C TutorialFor more information about the XML standard, see

The main differences between XML and HTML

XML is designed to carry data.

XML is not designed to replace HTML.

XML and HTML are designed for different purposes:

XML is designed to describe data, with a focus on the content of the data.

HTML is designed to display data, with a focus on the appearance of the data.

HTML is designed to display information, while XML is designed to describe information.

There is no action in the XML

XML is passive.

It may be a bit difficult to understand, but XML does nothing. XML is designed to structure, store, and transmit information.

Below is the note written by John to George, stored as XML:

<note>
<to>George</to>
<from>John</from>
<heading>Reminder</heading>
<body>Don't forget the meeting!</body>
</note>

This tag contains a title and comments. It also includes information about the sender and the recipient. However, this XML document is still doing nothing. It is merely pure information wrapped in XML tags. We need to write software or a program to transmit, receive, and display this document.

XML is free and extensible

XML tags are not predefined. You must 'invent' your own tags.

The tags used to mark HTML documents and their structure are predefined. The creators of HTML documents can only use those tags defined in the HTML standard (such as <p>, <h1>).

XML allows creators to define their own tags and document structure.

The tags in the above examples have not been defined in any XML standard. These tags were invented by the author of the XML document.

XML is a supplement to HTML

XML is not a substitute for HTML.

It is very important to understand that XML is not a substitute for HTML. In the future of Web development, the most likely scenario is that XML will be used to describe data, while HTML will be used to format and display these data.

Our best description of XML is: XML is a cross-platform tool for transmitting information, independent of software and hardware.

The role of XML in the future of Web development

XML will be ubiquitous.

When we see the rapid development progress of XML standards and the ever-changing speed at which a large number of software developers adopt this standard, it is really hard not to be amazed at how amazing it is.

We firmly believe that the role XML will play in the future of the Web will not be less than that of HTML, which has always been the cornerstone of the Web, and XML will become the most commonly used tool for all data processing and data transmission.