    <button class="btn btn-default" ng-click="y = undefined">Set to undefined (uninitialize)</button>
                                </p>
                                <p>
                                    <button class="btn btn-default" ng-click="y = '(999) 999-9999'">Set to (999) 999-9999</button>
                                </p>
                                <p>
                                    <button class="btn btn-default" ng-click="y = '(999) 999-9999 ext. 999'">Set to (999) 999-9999 ex