Example of AngularJS $http loading global variable

index.html

<!-- use $root.loading -->

script.js

app.config(['$httpProvider', function ($httpProvider) {
    $httpProvider.responseInterceptors.push(['$q', '$rootScope', function($q, $rootScope) {
        return function (promise) {
            return promise.then(function (response) {
                // Success
                $rootScope.loadingCount--;
                $rootScope.loading = $rootScope.loadingCount !== 0;

                return response;
            }, function (response) {
                // Error
                $rootScope.loadingCount--;
                $rootScope.loading = $rootScope.loadingCount !== 0;

                return $q.reject(response);
            });
        };
    }]);
}]);

app.run(['$http', '$rootScope', function ($http, $rootScope) {
    $rootScope.loadingCount = 0;
    $rootScope.loading      = false;

    $http.defaults.transformRequest.push(function (data) {
        $rootScope.loadingCount++;
        $rootScope.loading = $rootScope.loadingCount !== 0;

        return data;
    });
}]);