In the past, when someone wanted to design a document for use on the World Wide Web, they were generally limited to using basic HTML tags. Occasionally, a new feature would be provided by browser designers – for instance, Netscape offered a <BLINK> element that allowed users to produce flashing text.
Unfortunately, such improvements were limited to specific browsers – that is “blinking” text designed for the Netscape browser would not display properly on Microsoft Internet Explorer browsers. The feature was not adequately “standardized”, and people who used the new feature could only reach a limited audience.
The W3 (also known as the World Wide Web consortium) is the premier nonprofit organization that determines and promotes standards for interoperable technologies such as HTML and XML. When Web developers wanted to introduce a new HTML feature to a large audience, they had to submit a request to the W3. Unfortunately, submitting a recommendation for change to the W3 was a long and tedious process, often involving the approval of many organizations. Getting the public-at-large to accept these changes was even more difficult and time-consuming, since it involved the commitment and cooperation of large corporations such as Microsoft and Netscape.
With XML, Web developers
can introduce new tags, elements, and features to a Web document almost
immediately. Currently, major browsers
such as Microsoft
Internet Explorer and Netscape can support XML. A good way of thinking of
XML is to remember that the features of XML can be extended or "added
to" - that is, the user can specify new features and add them to a document.