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

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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.