$scope.widgetData = false;
        $scope.graphData = false;
        $scope.graphSelectorIndex = 0;

        $scope.graphSelector = [
            { 'byPeriod' : 'Periode'},
            { 'byHour' : 'Uur' },
            { 'byDay' : 'Dag'}
        ];

        $scope.graphSelectorByText = function (text) {
            switch (text) {
                case ('byPeriod'):
                    $scope.selector = 'byPeriod'
                    $scope.graphData = $scope.allGraphData.byPeriod;
                    $scope.graphType = 'Line';
                    break;
                case ('byDay'):
                    $scope.selector = 'byDay'
                    $scope.graphData = $scope.allGraphData.byDay;
                    $scope.graphType = 'Line';
                    break;
                case ('byHour'):
                    $scope.selector = 'byHour'
                    $scope.graphData = $scope.allGraphData.byHour;
                    $scope.graphType = 'Bar';
                    break;
            }
        }

        $scope.graphSelectorByInt = function (int) {
            switch (int) {
                case (0):
                    $scope.selector = 'byPeriod';
                    $scope.graphData = $scope.allGraphData.byPeriod;
                    $scope.graphType = 'Line';
                    break;
                case (1):
                    $scope.selector = 'byDay';
                    $scope.graphData = $scope.allGraphData.byDay;
                    $scope.graphType = 'Line';
                    break;
                case (2):
                    $scope.selector = 'byHour';
                    $scope.graphData = $scope.allGraphData.byHour;
                    $scope.graphType = 'Bar'
                    break;
            }
        }

        $scope.graphSelectorPrev = function () {
            $scope.graphSelectorIndex--;
            if ($scope.graphSelectorIndex < 0) {
                $scope.graphSelectorIndex = $scope.graphSelector.length-1;
            }
            $scope.graphSelectorByInt($scope.graphSelectorIndex);
            console.log($scope.graphSelectorIndex);

        }

        $scope.graphSelectorNext = function () {
            $scope.graphSelectorIndex++;
            if ($scope.graphSelectorIndex >= $scope.graphSelector.length) {
                $scope.graphSelectorIndex = 0;
            }
            $scope.graphSelectorByInt($scope.graphSelectorIndex);
            console.log($scope.graphSelectorIndex);
        }

<div class="controlls">
        <span class="btn_arrow previous inactive" ng-click="graphSelectorPrev()">Vorige</span>
        <p>{+ selector +}</p>
        <span class="btn_arrow next" ng-click="graphSelectorNext()">Volgende</span>
    </div>