As of 2013 all foreigners who want to work or intern in China must have a work visa (Z Visa) in hand when they arrive in China. This is the Chinese visa law, and there is no "grace" or "probationary period" nor "exclusions" nor "exemptions". The scam agents will even try to tell you that the law was just "ammended last week"!
No matter what the sales people and recruiting agents tell you - THERE ARE NO EXCEPTIONS! They will try to convince you to come to China on a L, F, or M visa. If you listen to them you will have a 50% chance of spending your China adventure behind bars like the 2,185 expats that were jailed in 2014, then fined $2,000 and deported with a 5 year reentry ban and a felony conviction on their record. You can read more about this subject at the below links friends. Trust the law - not some stranger on skype!
If anyone tries to recruit you for China on any other visa, please report them immediately to tips[at]ChinaScamPatrol.org. We do not need your name only the details of the agent trying to recruit you.