$("form.contact").validate({
  //onfocusout: function(element) { $(element).valid(); },
  rules: {
    email: { required:true, email: true},
    username: { required: true }
  }, 
  // [optional] custom messages
  messages: { 
    email: { required: "custom required field message", email: "Custom email message" },
  }
  // [optional] custom error placement
  errorPlacement: function(error, element) {
    
  } 
});

// blur 
$(element).blur(function() {
  $("form.contact").validate().element($this);  
});