H1b cap exempt clarification

Hi all,
I have few questions regarding my h1b petition

  1. Through my previous employer I had got my H1B in jan 2011 valid through June 2012 while in India.

  2. I traveled to US in May '2011 and stayed in the US from May’2011 - Aug 2012 (12 months, yes I have applied for extension while in US) and returned back to India.

  3. My H1B got expired in June’2012.

  4. I left job at employer ‘X’ and joined employer ‘Y’.

The question is, am I eligible for h1b cap exempt?
if yes, how long will my petition be valid ?

How to check the petition validity online?

Does employer ‘X’ who provided me visa could revoke my petition, after I left the company. ?

You are cap-exempted for 6 years (which ends in Aug 2018). The new cap-exempt petition can be applied even if old employer has withdrawn their petition.

Thank you Saurabh for quick response.