XML (eXtensible Mark up Language) is not as popular like HTML or PHP in web development but it is known and vital in so many ways. Sitemap and RSS feeds are normally in XML format. Some flash action scripts are dependent in XML in uploading or modifying files to display.
XML document unlike HTML is self-describing. You are the author of your XML document. You can create and describe your own tags. Despite that XML needs other languages or applications to display, it is very essential in structuring data, a reason why it is famous for sitemaps and feeds.
See HTML and XML coding comparison below:
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en" dir="ltr">
<title>Your Title </title>
<td>This is my first XML document</td>
<?xml version="1.0" encoding="iso-8859-1"?>
<SUBJECT>This is my first XML Document</SUBJECT>
Despite that HTML can already display the data; the table tags are rigid. We cannot define a table tag in HTML other than <table> and the same concept with all the other tags. But with XML, we defined all the tags: <MEMO>, <TO>, <FROM> and so on.
XML is not a stand alone language. It needs partners like HTML or PHP to be called and display results. Others might find this process as too much effort but the truth is, once you have structured your XML, it is easier to maneuver and display output on the web. Also, you can modify your XML and control data without going through your HTML or PHP files. Example is XML’s popularity in flash photo galleries run by action scripts. Artists or coders will simply add photos and update the XML file where images are being described. Changes will appear upon refreshing the photo gallery.
Another significance of XML is its being a standard compliance language and very easy to manipulate. It compliments almost all of the applications online especially those systems that require data interchange formats like legacy systems.
XML might be not as famous like other languages to common coders or laymen online users but its importance is greater upon looking deeper on the foundation of different web systems and applications like sitemaps, feeds, xml for action scripts, syndicated apps and more.