Resignation vs Next Step


In case or by chance, If i have resigned my job(without new offer) with current employer,

  1. How it gonna impact my H1B visa?
    FYI My extension was filed(rec’d RFE and did response). Now, i’m in India, i have completed 2.5 year in USA already.

  2. Can I reapply again with new employer(when i got new offer)?
    2a. Do i need to be with any employer without any gap?

  3. What things i need to be care to get/collect from my employer or any thing i need consider before i resign?

Please advise me. thanks in anticipation.
You guys are do SO MUCH HELP… I appreciate, keep continue.