title: Ajax remote validate wordpress username and email with Jquery validation plugin
body: <p>Does anyone know how to validate wordpress username and email with jquery validation plugin?</p>
  
  <p>I'm trying to check if username and email exists with validation's remote method.</p>
  
  <p>And I notice wordpress has functions like username_exists and email_exists, is there a quick way to do the job?</p>
  
  <p>Plz help~</p>