cakephp client/model validation for adding comment

i am done coding for add comment using jquery ajax开发者_如何学Go and its working fine.

I want to do validation while adding the comment. as of now its taking empty comment also.

what are the best ways to add validation for add comment

Please read the data validation chapter of the docs! Then if you are still stuck, post your attempt at solving the problem, then you will get an answer.