Because u have valid OPT I think you can work anywhere till your OPT expires.Once u get H1B approval I do not think u can work in other places.

My issue is different: my Opt expired on September but I had my advisor extend my opt  (Threre is a new gap rule that covers the opt GAP) but my advisor extended it till September end assuming that  BY October 1 I will have decision from USCIS. Now my question

1.       what happens if I do not get decision by oct 1?Can I still work in my current job till USCIS give decision or do I need to leave company and country by the end of September?

           2. Will I get some period to straight out my status if my h1 get denied?

Please help me seniors. anybody in this type of case. I really appreciate your suggestion and thoughts.