在AngularJS网页上自行调用javascript函数

<script type="text/javascript">
    // Should I defne it here like this completely outside the self invoking
    // function with or without var keyword
    getData = function (reqData) {
        alert(reqData); // Ajax call here...
    };

    (function () {

        // Should I defne it here like this? 
        getData = function (reqData) {
            alert(reqData); // Ajax call here...
        };

        //Should I have to use the var key word like so 
        var getData = function (reqData) {
            alert(reqData);// Ajax call here...
        };

        PatientCategoryController = function ($http,$scope,uiGridConstants) {

            // Should I defne it here like this inside the controller? 
            getData = function (reqData) {
                alert(reqData);// Ajax call here...
            };

            //Should I have to use the var key word inside the controller?
            var getData = function (reqData) {
                alert(reqData);// Ajax call here...
            };

            // Or should I define the function on the $scope object like so?
            $scope.getData = function (reqData) {
                alert(reqData);// Ajax call here...
            };

            angular.element(document).ready(getData('someDataToPass'));
        }
        PatientCategoryController.$inject = ['$http','$scope','uiGridConstants'];
        angular.module('demoApp',['ui.grid','ui.grid.autoResize','ui.grid.pagination']);
        angular.module('demoApp').controller('PatientCategoryController',PatientCategoryController);
    }());
</script>

我的问题是如何定义这个功能？应该在$scope对象上定义吗？或者应该与控制器相提并论？或者我应该在自调用函数之外完全定义它？

同样在类似的行中我应该定义javascript对象,它将保存ajax调用可能需要的数据.

我开始构建这个页面,在某些时候,javascript开始表现得很糟糕,所以我不得不从头开始.这就是我提出这个问题的原因.
在过去,我已阅读并尝试了解javascript,但除了在浏览器方面,我还没有做过任何严肃的javascript编程.这个应用程序本身在Asp.Net mvc.所以我对javascript一直没有信心并且不断陷入困境.请指导我.