Both, always! It is important to have client side to ensure better UX and avoid unnecessary requests to the server.
On the other side, do it on the server side always as validation is very necessary to mantain integrity of your data. Also, you can plug your server to different clients and don't have to remember to do all of those validations again ;)
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Both, always! It is important to have client side to ensure better UX and avoid unnecessary requests to the server.
On the other side, do it on the server side always as validation is very necessary to mantain integrity of your data. Also, you can plug your server to different clients and don't have to remember to do all of those validations again ;)