Requirements for getting married on visiting visa in canada

Hi,
My girl friend is in canada on student visa who hails from india. Am living in india right now and i have been collecting information for application to visit canada. My question is if i reach canada on visit visa somehow and we plan to get married, may i know how can i legally can do so?(My girl friend and I are from different religions, So i want to get legal certifcate for my marriage) I have heard about "No objection certificates" and marriage licenses but i didnt get anything clarified in my mind yet.So could you please provide me the above information.
Thanks
Sameer