<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <script src="http://apps.bdimg.com/libs/angular.js/1.2.16/angular.min.js"></script>
</head>
<body ng-app="copyExample">
  <div ng-controller="ExampleController">
    <form novalidate class="simple-form">
      Name: <input type="text" ng-model="user.name" /><br />
      E-mail: <input type="email" ng-model="user.email" /><br />
      Gender: 
      <input type="radio" ng-model="user.gender" value="male" />
      male
      <input type="radio" ng-model="user.gender" value="female" />
      female
      <br />
      <button ng-click="reset()">RESET</button>
      <button ng-click="update(user)">SAVE</button>
    </form>
    <pre>form = {{user | json}}</pre>
    <pre>master = {{master | json}}</pre>
  </div>

  <script>
  angular.module('copyExample', [])
  .controller('ExampleController', ['$scope', function($scope) {
    $scope.master= {};
    
    var test1;
    console.log(angular.copy(test1));//undefined
    var test3=null;
    console.log(angular.copy(test2));//undefined

    var test2 = "a";
    // console.log(angular.copy(test2,test2));//error!!

    $scope.update = function(user) {
      // Example with 1 argument
      $scope.master= angular.copy(user);
    };

    $scope.reset = function() {
      // Example with 2 arguments
      angular.copy($scope.master, $scope.user);
      console.log($scope.master);
      console.log($scope.user);
    };

    $scope.reset();
  }]);
  </script>
</body>
</html>