Thanks, Simon and Bird.
Bird, I tested your latest code and it works on Chrome but still not working in Firefox 14. I haven't tested it yet on IE9 because I have IE8 and well it doesn't work on IE8 but at least I got feedback from IE8 error log:
Code:
"Can't move focus to the control because its invisible, not enabled, or of a type that does not accept the focus"
Maybe if we solve that problem then it will work on IE and Firefox!
Or maybe there is a type on your code?