If I get H1b approved for 2014 quota, can I come to USA on H4?

Hi,

I am working in USA on H1. My wife is in India and her employer has applied for her H1. Once her H1 gets approved (say on10th May 2013), can she come to visit me on H4? In that case, does her H1 get affected? If she comes on H4 and later files for COS, can she start working on H1 from October?

What are chances for COS denial?

Thanks,

Gaurang

Please suggest as i also would be having same query.