About XML

The Facts

XML stands for Extensible Markup Language. XML is designed to transport and store data, improving the functionality of the Web by providing information in a ways that are more accurate, flexible and adaptable. Unlike HTML (Hyper-text Markup Language), it doesn't have a fixed format that uses a single and predefined markup language. XML is extensible and uses "metalanguage," which means that it is a language that describes other languages. Having this capability allows XML users to design their own markup languages for various types of documents.

The common misconception about XML is that people think it is an extension of HTML. XML and HTML, however, do not exist in the same layer of markup technology. Contrary to what many people think, XML is not just a method of extending HTML by adding new tags. XML uses an infinitely large set of possible tags as opposed to a small set of standard tags used by HTML. Furthermore, XML does not follow a standard behavior at all, while HTML does in most cases. Simply put, an XML is a simplified form of a SGML (Standard Generalized Markup Language) rather than an extension of HTML.

XML has many different uses such as, Web publishing, Web searching, general applications, e-business applications, metadata applications and pervasive computing. For Web publishing, XML allows users to create and customize interactive pages using stored data. For Web searching and automating Web tasks, XML makes it easy to return useful results while searching the Web by its ability to define the content of the document. When used for general applications, XML allows users to access information by using a standard method. This makes it easier for different applications and devices to store, transmit or display and use the data. In e-business applications, XML can provide readily accessible information for transactions between businesses or between consumers and businesses by implementing EDI (Electronic Data Interchange). XML makes it less difficult to utilize metadata applications by providing them in a portable and reusable format. XML can also provide portability when in use with pervasive computing, utilizing structured information for wireless gadgets such as PDAs (Personal Digital Assistants) and cell phones.

Internet Explorer and Firefox can be used to view raw XML files. To use Netscape Navigator, Opera or Safari, one would need to right-click the page and select "View Source" in order to view raw XML, not the element text. Note that XML files cannot be displayed like HTML pages. To see a sample of an XML document please refer to the link under "Resources" entitled "XML Document." The root and child elements are displayed in color-coded form. There is a plus (+) or a minus (-) sign located on the left of the elements that can be expanded by clicking on them. If preferred one can view the XML source without using the + or - signs by going to the browser menu and choosing "View Page Source" or "View Source."

The benefits of XML can best be described when being compared with HTML. Some of the benefits that XML can provide are as follows:

1) XML is less cumbersome to use than HTML. Utilizing XML allows the authors and designers to invent their own markup elements.
2) XML uses a greater but simpler form of hypertext linking abilities compared to HTML. It can also provide better performance for browser presentations and provides richer information.
3) XML also provides better compression of data, which can lead to higher performance.