title: Display button only on form input change in angular.js
body: <p>HTML:</p>
  
  <pre><code>&lt;ul&gt;
      &lt;li&gt;&lt;a&gt;&lt;i class="icon-white icon-save"&gt;&lt;/i&gt;&lt;/a&gt;&lt;/li&gt;
  &lt;/ul&gt;
  
  &lt;form&gt;
       &lt;input type="text" value="{{ selectedUser.firstname }}" ng-model="selectedUser.firstname"&gt;
       &lt;input type="text" value="{{ selectedUser.lastname }}" ng-model="selectedUser.lastname"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>I am dealing with user objects fetched from my REST API. So basically there is a list of users. On click the above form is revealed.</p>
  
  <pre><code>function UserController($scope, User){
      $scope.users = User.query();
  
      $scope.selectedUser = null;
  
      $scope.select = function(user){
          $scope.selectedUser = user;
      }
  }
  </code></pre>
  
  <p>I want to display the save link only when form values have changed. Any ideas how to do this with angular.js?</p>