Manually Check Validity

<!DOCTYPE html>
<html>

  <head>
    <link data-require="bootstrap-css@3.0.1" data-semver="3.0.1" rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.0.1/css/bootstrap.min.css" />
    <script src="http://code.angularjs.org/1.2.5/angular.js" data-semver="1.2.5" data-require="angular.js@1.2.5"></script>
    <script data-require="jquery@*" data-semver="2.0.3" src="http://code.jquery.com/jquery-2.0.3.min.js"></script>
    <script data-require="bootstrap@3.0.1" data-semver="3.0.1" src="//netdna.bootstrapcdn.com/bootstrap/3.0.1/js/bootstrap.min.js"></script>
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
  </head>

  <body ng-app="app" ng-controller="NewUserController">
    <h1>Add New User</h1>
    <form name="userForm" novalidate>
      <div class="form-group" show-errors>
        <label class="control-label">Name</label>
        <input type="text" class="form-control" name="name" ng-model="user.name" required placeholder="Name" />
      </div>
      <div class="form-group" show-errors>
        <label class="control-label">Email</label>
        <input type="email" class="form-control" name="email" ng-model="user.email" required placeholder="Email" />
      </div>
      
      <button class="btn btn-primary" ng-click="save()">Add User</button>
      <button class="btn btn-link" ng-click="reset()">Reset</button>
    </form>
  </body>

</html>

module = angular.module('app', []);

module.directive('showErrors', function($timeout) {
    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
        inputNgEl.bind('blur', function() {
          el.toggleClass('has-error', formCtrl[inputName].$invalid);
        });
        
        scope.$on('show-errors-check-validity', function() {
          el.toggleClass('has-error', formCtrl[inputName].$invalid);
        });
        
        scope.$on('show-errors-reset', function() {
          $timeout(function() {
            el.removeClass('has-error');
          }, 0, false);
        });
      }
    }
  });

module.controller('NewUserController', function($scope) {
  $scope.save = function() {
    $scope.$broadcast('show-errors-check-validity');
    
    if ($scope.userForm.$valid) {
      alert('User saved');
      $scope.reset();
    } else {
      alert("There are invalid fields");
    }
  };
  
  $scope.reset = function() {
    $scope.$broadcast('show-errors-reset');
    $scope.user = { name: '', email: '' };
  }
});

/* Styles go here */
body {
  padding: 10px;
}