The letters XML stand for Extensible Markup Language. This is a great language to know and even better to learn for it is not very difficult to learn. Certifications in this language are also available to earn on line in the comfort of home with a computer at the speed of preference. First the basics should be mastered in HTML and then in XML. That is not a problem either as all the details are available with an online editor in both HTML and XML free of charge for practice and preparation for the certification test. There are quiz questions and samples to view and edit for oneself at the great 3W school web site. The 3W school website is maintained for keeping the standard in the World Wide Web consortium level of expertise.

Why was XML developed? The main purpose of XML is to transport data and to store data. To learn XML it is very important to have a good foundation in HTML and Java Script since those are basic building blocks for XML. Although XML is very similar to HTML it does not have predefined tags. The tags must be defined by the author. This is a language that is has been designed to be self-descriptive. The 3W Consortium recommends this language.

The functions of HTML and XML are their main differences. HTML was designed to display data. XML was designed to store and transport data. The most common use of XML which is as prevalent as HTML on the web is to simplify the storage of data and the sharing of data. For example, with dynamic data in an HTML document it is much easier to store the files in XML in the document than to rewrite it many times in HTML to display it. There are many great uses and advantages to using XML in web pages.

1. XML simplifies hardware and software platform changes; XML facilitates upgrading to new systems without losing data.

2. XML makes data more user accessible; Data can be processed by "reading machines," (PDA's, voice machines, news feeds) and is available to the blind.

3. Many internet languages have been created with XML; XHTML, WSDL, WAP, WML, RSS for news feeds, RDF and OWL for ontology and SMIL, each of these are a type of descriptive language on line.

The structure of XML language in its storage capacity is a tree. The 'root' is the basic start of an XML document and then come the branches and the leaves of the document. The root is the parent of the sum of all other elements in the document. The document tree is formed from a root then branches to child elements.