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 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 David from Peter, stored as XML:
<note> <to>David</to> <from>Li</from> <heading>Reminder</heading> <body>Call 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 a software and hardware independent tool for carrying information.
XML Simplifies Data Sharing
In the real world, computer systems and databases contain data in incompatible formats.
XML data is stored in plain text format. This provides a software- and hardware-independent way of storing data.
This makes it much easier to create data that different applications can share.
XML Simplifies Data Transport
With XML, data can easily be exchanged between incompatible systems.
One of the most time-consuming challenges for developers is to exchange data between incompatible systems over the Internet.
Exchanging data as XML greatly reduces this complexity, since the data can be read by different incompatible applications.
XML Simplifies Platform Changes
Upgrading to new systems (hardware or software platforms), is always very time consuming. Large amounts of data must be converted and incompatible data is often lost.
XML data is stored in text format. This makes it easier to expand or upgrade to new operating systems, new applications, or new browsers, without losing data.
XML Makes Your Data More Available
Since XML is independent of hardware, software and application, XML can make your data more available and useful.
Different applications can access your data, not only in HTML pages, but also from XML data sources.
With XML, your data can be available to all kinds of "reading machines" (Handheld computers, voice machines, news feeds, etc), and make it more available for blind people, or people with other disabilities.
Written By LHTP Limited [http://www.learnhowtoprogram.com/]
Keywords:
Introduction to XML
| File | Extension | Size (bytes) | Modified Date |
|---|---|---|---|
| 14.zip | .zip | 242 | 23/03/2009 15:34:40 |
You are not currently logged on.
You must be a registered member to comment on our resource pages.
It is free to register. You can register here Registration Form
