Which is better to do client side or server side validation?
In our situation we are using
I will suggest to implement both client and server validation it keeps project more secure......if i have to choose one i will go with server side validation.
You can find some relevant information here https://web.archive.org/web/20131210085944/http://www.webexpertlabs.com/server-side-form-validation-using-regular-expression/