XML may be a software- and hardware-independent tool for storing and transporting data.
Why Study XML?
XML plays a crucial role in many IT systems.
For this reason, it's important for all software developers to possess an honest understanding of XML.
Before you continue, you ought to even have a basic understanding of:
- HTML
- JavaScript
- If you would like to review these subjects first.
What is XML?
- XML stands for EXtensible terminology
- XML may be a terminology very similar to HTML
- XML was designed to store and transport data
- XML was designed to be self-descriptive
- XML may be a W3C Recommendation
- XML doesn't DO Anything
- Maybe it's a touch hard to know , but XML doesn't DO anything.
This note may be a note to Tove, from Jani, stored as XML:
Tove
Jani
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
The note is sort of self-descriptive. it's sender and receiver information. It also features a heading and a message body.
But still, this XML document doesn't DO anything. XML is simply information wrapped in tags. Someone must write a bit of software to send, receive, store, or display it:
Note
To: Tove
From: Jani
Reminder
Don't forget me this weekend!
The Difference Between XML and HTML
XML and HTML were designed with different goals:
- XML was designed to hold data - with specialise in what data is
- HTML was designed to display data - with specialise in how data looks
- XML tags aren't predefined like HTML tags are
- XML doesn't Use Predefined Tags
- The XML language has no predefined tags.
The tags within the example above (like and ) aren't defined in any XML standard. These tags are "invented" by the author of the XML document.
HTML works with predefined tags like , , , etc.
With XML, the author must define both the tags and therefore the document structure.
XML is Extensible
Most XML applications will work needless to say albeit new data is added (or removed).
Imagine an application designed to display the first version of note.xml ( <heading> ).
Then imagine a more moderen version of note.xml with added and elements, and a removed <heading>.
The way XML is made , older version of the appliance can still work:
2015-09-01
08:30
Tove
Jani
<body>Don't forget me this weekend!</body>
XML Simplifies Things
- It simplifies data sharing
- It simplifies data transport
- It simplifies platform changes
- It simplifies data availability
Many computer systems contain data in incompatible formats. Exchanging data between incompatible systems (or upgraded systems) may be a time-consuming task for web developers. Large amounts of knowledge must be converted, and incompatible data is usually lost.
XML stores data in plain text format. This provides a software- and hardware-independent way of storing, transporting, and sharing data.
XML also makes it easier to expand or upgrade to new operating systems, new applications, or new browsers, without losing data.
With XML, data are often available to all or any sorts of "reading machines" like people, computers, voice machines, news feeds, etc.
XML may be a W3C Recommendation
XML became a W3C Recommendation on February 10, 1998.