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

app.controller('MainCtrl', function($scope) {
  $scope.name = 'World';
});
<!DOCTYPE html>
<html ng-app="plunker">

<head>
  <meta charset="utf-8" />
  <title>AngularJS Plunker</title>
  <script>
    document.write('<base href="' + document.location + '" />');
  </script>
  <link rel="stylesheet" href="style.css" />
  <script data-require="angular.js@1.5.x" src="https://code.angularjs.org/1.5.8/angular.js" data-semver="1.5.8"></script>
  <script src="app.js"></script>
</head>

<body ng-controller="MainCtrl">
  <div>
    <form name="formDemo" class="form-horizontal" novalidate>
      <div class="form-group" ng-class="[{'has-error':formDemo.$submitted && formDemo.formName.$invalid}]">
        <label for="formName" class="control-label">Name</label>
        <input type="text" class="form-control col-sm-10" name="formName" id="formName" required>
        <!--<input type="text" class="form-control col-sm-10" ng-model="name" name="formName" id="formName" required>-->
      </div>
      <div class="form-group">
        <label for="formAge">Age</label>
        <input type="number" class="form-control" name="formAge" id="formAge" required>
        <!--<input type="number" class="form-control" ng-model="age" name="formAge" id="formAge" required>-->
      </div>
      <div class="form-group">
        <input type="submit" ng-click="Submit()" class="form-control btn btn-primary">
      </div>
    </form>
  </div>

  <div ng-class="[{'text-danger':formDemo.$invalid}]">
    <h4>Form Details</h4> Form Valid : {{formDemo.$valid}}
    <br> Form Invalid: {{formDemo.$invalid}}
    <br> Form Dirty: {{formDemo.$dirty}}
    <br> Form Submitted: {{formDemo.$submitted}}
    <br> Name Invalid: {{formDemo.formName.$invalid}}
  </div>
</body>

</html>
/* Put your css in here */