Facing lag problem

I have made my game and for testing purporses, I tried on the Web it works fine, but now that I am testting on the phone and ipad it is lagging a lot, and at times it crashes.

I am testing my game via cocoojs, can anyone suggest to me how can I improve so it doesn't lag or crashes ...

Please any suggestion would be helpful.

Thank you

Tutorial : https://www.scirra.com/tutorials/298/pe ... bile-games