Why do i have a blank space on the right of my website?

It only shows the blank side on iphone and blackberry, small screen sizes, but not desktop
after using display: none tag, i found that the problem comes from the inner div
here is the code for these:

#outerdiv{ width:100%; height: auto; background:; margin-top:; }

#innerdiv { width:80%; height: 100px; margin: -350px auto auto; background: url(xxx.jpg) no-repeat top, url(xxx.jpg) no-repeat bottom, url(xxx.jpg) repeat-y center; margin-top:10px; }

when i set the right and left margin to 0px, the blank side disapears, i can't see why, and when i hide the inner div, no blank side as well

That is a BIG margin for phone use. We would need to see the code surrounding that to determine what is the real problem, something may be overlapping the rest of the screen.

There's something mistake in your layout or html Div coding, you need to check it out again and have to manage layout. Try this may be this could help you http://www.aaawebstore.com/