angular_jade_form.jade

form(name='registration')
    .form-group
        label(for='username') Username
        input#username.form-control(type='text', required='', ng-minlength='3', 
          name='username', ng-model='user.username')
        ng-messages(for='registration.username.$error', 
          ng-show='registration.username.$dirty && registration.username.$invalid', role='alert')
            ng-message(when='required') Username is required
            ng-message(when='minlength') Username must be at least 3 characters long