Thanks friends that explains me a lot i will use your answer for my further works... :)
And also i am planing to make a game like this
<img src="http://www.canvasdemos.com/wp-content/uploads/2010/01/canvas-invaders.jpg" border="0">
Is there any idea to make the enemy movements. Because i am thinking which property and what event to use for them to make them movie to both ends???
I have updated my .capx file