Show error on blur, and use myFormSubmitted

errors-onblur.css

.form-group .help-block {
    display: none;
}
.form-group.has-error .help-block {
    display: block;
}

errors-onblur.html

<div>
  <form name="myForm" novalidate>
      <div class="form-group" ng-class="{true: 'has-error'}[myFormSubmitted && myForm.firstName.$invalid]" show-errors>
          <label class="control-label">First Name</label>
          <input type="text" class="form-control" name="firstName" maxlength="256" ng-maxlength="256" required/>
          <p class="help-block" ng-show="myForm.firstName.$error.required">Enter your first name</p>
          <p class="help-block" ng-show="myForm.firstName.$error.maxlength">Your first name is too long</p>
      </div>
      <div>
          <button class="btn btn-primary" ng-click="myFormSubmitted=true">Continue</button>
      </div>
  </form>
</div>

errors-onblur.js

// http://blog.yodersolutions.com/bootstrap-form-validation-done-right-in-angularjs/
//show errors on blur
angular.module('myApp')
  .directive('showErrors', function() {
    return {
      restrict: 'A',
      require: '^form',
      link: function(scope, el, attrs, formCtrl) {
        // find the text box element, which has the 'name' attribute
        var inputEl = el[0].querySelector('[name]');
        // convert the native text box element to an angular element
        var inputNgEl = angular.element(inputEl);
        // get the name on the text box
        var inputName = inputNgEl.attr('name');

        // only apply the has-error class after the user leaves the text box
        var blurred = false;
        inputNgEl.bind('blur', function() {
          blurred = true;
          el.toggleClass('has-error', formCtrl[inputName].$invalid);
        });

        scope.$watch(function() {
          return formCtrl[inputName].$invalid;
        }, function(invalid) {
          // we only want to toggle the has-error class after the blur
          // event or if the control becomes valid
          if (!blurred && invalid) {
            return;
          }
          el.toggleClass('has-error', invalid);
        });
      }
    };
  });