Struts 2 Client & Server Side Validation

[Struts Developer]

Hello, In our current project are using struts 2.0 and would like to take
advantage of the struts validation framework. We would like our form fields
to be validated both on the client and server side. If i have "VALIDATE =
TRUE" in the form  field will the validation happen only on client side? For
some reason if the client side validation does not happen will struts do the
validation on the server side for the same field using the same XML
configuration files?