MXML is a declarative XML-based language which is used to lay out user interfaces in Flex. MXML is mainly used to declaratively lay out the user interfaces of Flex applications, but it can also be used to create complex business logic and behaviors. As I mentioned earlier, MXML is based on XML standards which makes it easy to understand and learn. The MXML acronym does not have any official meaning, but some believe that it stands for Multimedia eXtensible Markup Language.
Let's take a look at the anatomy of a general MXML file. All MXML documents begin with an XML declaration. This declaration is used by the XML standard to specify the type of document and a small amount of information about versioning (for the parsers) and encoding of the document. You don't need to have an XML declaration, but you should have it as a good practice.
The following is an XML declaration:
<?xml version="1.0" encoding="utf-8"?>
The next line is where you declare your Application
tag as a...