#32 - Can I Study in USA While on H1B Visa - MS in CS?

Hi All, I am on H1B in the US and it's my first year into H1B, so that means I have at least 2 years left on H1B. Now, I am planning to do 1 year MS in CS, and have following questions: 1. Will my H1B remaining period be valid after 1 year? 2. If yes, how many years on H1B will be left post MS? 3. May my employer request for an extension as well, later on, post MS? Thanks in advance,