9.4 Class body

A class body may contain variable definitions, namespace definitions, function definitions, and statements:

class A
{
    static var x
    static function f() {}
    var y
    function g() {}
    trace("class loaded")
}

Definitions result in class or instance traits depending on whether the static attribute occurs in their definition.
Statements and initializers of static variables are added to the static initializer method of the class. The static initializer is called once, when the class is defined at runtime. The static initializer can be used to initialize variables of the class object and to invoke methods that are external to the current class.
Initializers of instance variables are added to the instance initializer method.
The scope chain of methods contained by the class body includes the class object, the base class objects (from most derived the least derived), and the global object.

Note that it is not an error to define a class and instance property with the same name, as in the following example:

class A {
    static var x
    var x
}

It is also not an error to define a class property with the same name as a visible class property in a base class:

class A {
    static var x
}
class B extends A {
    static var x
}

Current page: http://livedocs.adobe.com/specs/actionscript/3/as3_specification84.html