I read many article but i am still confused. Could any one tell me what is the
difference between MX and spark? If you try to explain with example that will
be good for me.

Spark is a new theme introduced (in addition to Halo) with Flash builder 4 (Flex4). These two themes support different kinds of styles.When you want to customize the user interface of a Flex application you have to put hands on its visual components. The first thing to know when approaching this task is that there are two "families" of components. The first family of components is mx (sometimes referred to as halo). These are the components included in the Flex 3 framework, which are still available in the Flex 4 library. The second family of components is spark, which is a whole new set of components that enhance the possibilities of developing and customizing Flex applications.

Last March Macromedia released Flash MX with a compelling new vision for the product: the animation and design software would henceforth be groomed as a rich Internet application platform.

Really very good and technical answer. I appreciate the information you have provided. Thanks a lot. Keep it up...

if i know i tell that. better for u ask any expert.

MX is a more complete and efficient set of elements for pc and web browser applications, but they had unreliable skinning guidelines.

Spark provides more consistent skinning guidelines, facilitates right-to-left text, and has touch-enabled elements for mobile.