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What XML is (and what it isn't)...
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botman
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Default What XML is (and what it isn't)... - 03-06-2004

XML is "Extensible Markup Language".

XML is a Data Definition language. That is, it defines how data is represented. XML is kind of like HTML on steroids. Anyone who knows what HTML is (and what it can do), can generally understand what XML is and what it can do. The really nice thing about XML is that you can create your own 'tag' types (whereas in HTML, you are limited to the 'tag' types that are defined as part of the HTML language, and you can't extend HTML to create your own tags).

XML (like HTML) is NOT code. XML doesn't execute anything. You can't compile XML into an executable application. XML is only meant to store data that can then be processed by an XML interpreter (just like you need a Web browser application, like Internet Explorer or Netscape Navigator, to view a HTML rendered web page).

Based on the comments in many of the threads here, many people seem to believe that XML is some sort of "machine independant" code execution thingy, and this simply isn't true.

You can't execute XML code. If you want to store data in an XML format, you still need to create application code that does something with this data.

There ARE plenty of freely available XML parsers that will parse the XML data and allow you to retrieve the data stored in the XML file, but once the data has been retrieved, you still have to create some application code that does something with that data (just like you could retrieve tag data from an HTML file, but the string http://www.microsoft.com doesn't do anything magical just by itself). You have to create application code that DOES SOMETHING with that data.

XML is merely a nice way to organize configuration type data so that it can be retrieved by application code later on.

One not too nice thing about XML is that it is difficult to read/edit with just a text editor for the average novice computer user. It would be similar to creating all your HTML code using Notepad.exe. It CAN be done, but nobody in their right mind would REQUIRE users to create web pages using Notepad.exe

botman
  
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