[angularjs] Angular.js directive dynamic templateURL

I have an example about this.

<!DOCTYPE html>
<html ng-app="app">

  <head>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
  </head>

  <body>
    <div class="container-fluid body-content" ng-controller="formView">
        <div class="row">
            <div class="col-md-12">
                <h4>Register Form</h4>
                <form class="form-horizontal" ng-submit="" name="f" novalidate>
                    <div ng-repeat="item in elements" class="form-group">
                        <label>{{item.Label}}</label>
                        <element type="{{item.Type}}" model="item"></element>
                    </div>
                    <input ng-show="f.$valid" type="submit" id="submit" value="Submit" class="" />
                </form>
            </div>
        </div>
    </div>
    <script src="https://code.jquery.com/jquery-1.10.2.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.2/angular.min.js"></script>
    <script src="app.js"></script>
  </body>

</html>

angular.module('app', [])
    .controller('formView', function ($scope) {
        $scope.elements = [{
            "Id":1,
            "Type":"textbox",
            "FormId":24,
            "Label":"Name",
            "PlaceHolder":"Place Holder Text",
            "Max":20,
            "Required":false,
            "Options":null,
            "SelectedOption":null
          },
          {
            "Id":2,
            "Type":"textarea",
            "FormId":24,
            "Label":"AD2",
            "PlaceHolder":"Place Holder Text",
            "Max":20,
            "Required":true,
            "Options":null,
            "SelectedOption":null
        }];
    })
    .directive('element', function () {
        return {
            restrict: 'E',
            link: function (scope, element, attrs) {
                scope.contentUrl = attrs.type + '.html';
                attrs.$observe("ver", function (v) {
                    scope.contentUrl = v + '.html';
                });
            },
            template: '<div ng-include="contentUrl"></div>'
        }
    })