title: ASP.NET MVC 3: model-level client-side or remote validation
body: <p>I need to do some model-level validation in an MVC 3 edit page.  (To be specific, I need to confirm that either Field A or Field B is filled in, but not both and not neither.)  </p>
  
  <p>I want to perform client-side validation as well as server-side validation, which means either using remote validation or implementing duplicate validation code.  I'm OK with either.  </p>
  
  <p>I've read a number of posts on rolling your own server-side model-level validation, but none that deal with also implementing client side validation.  (I don't know -- I'm sure someone out there can tell me -- whether model-level client-side validation is easy to set up with jQuery validation.)  </p>
  
  <p>I've also read about implementing your own remote validation from scratch, which I may have to do since the Remote attribute is property-level only.</p>
  
  <p>I've read <a href="https://stackoverflow.com/questions/4410025/client-side-model-level-or-form-level-validation-with-asp-net-mvc3">this question</a>, which is identical to mine, but the only link that's really on-point doesn't seem to say what the answerer says it says.  </p>
  
  <p>So, my question:  is there an easy, relatively low-effort way to implement server+client model-level validation, with or without a remote component?  And is there a nice blog post or web page somewhere that explains this?  </p>