The below two links take you to a couple of posts that contain some information about contracts for foreign teachers teachers in Changchun and to an extent China as a whole.
You may find some of what I have written quite harsh and cynical (you may think I am an angry cynical laowai
which I’m not – just my being back in the UK has given me more of a perspective on what it was like at the time and I feel obliged to let others know!! 
) and that’s because the bottom line is It’s better to be safe than sorry.
Some come to Changchun and never experience any of problems related to contracts but most will at some stage have one contractual issue or another to resolve with their employer.
I’m not saying everyone is a crook out to deceive you, but you must not be blinded by western naivety. I have been messed around, had contracts dishonoured, owed salary, threatened and lied to – the list goes on. I have also had good experiences with contracts, though to be honest, they are far fewer than the bad ones- which Is why I hope this helps others.
I have had a lot of experience with various working contracts from different establishments in Changchun and the following two posts are some advice I’d offer having the benefit of heignsight !
Any questions feel free to email me –
This final link takes you to all the contract related pages on my blog: