How to save/load web-app setting in ionic framework after we close it?

I Have this setting list of background color in my app (white and black), When I choose Black, the background changes to black but after I close the app, it turns back again to white which is the default color. Anyone know how to save setting and load it when the app is re-opened ?

I recommend creating a service (/factory) for managing app settings:

myApp.factory('SettingsFactory', [function() {

    var _settingsKey = "appSettings",
        defaultSettings = {
            bgColor: #fff
        };

    function _retrieveSettings() {
        var settings = localStorage[_settingsKey];
        if(settings)
            return angular.fromJson(settings);
        return defaultSettings;
    }

    function _saveSettings(settings) {
        localStorage[_settingsKey] = angular.toJson(settings);
    }

    return {
        get: _retrieveSettings,
        set: _saveSettings,
        getBgColor: function() {
            return _retrieveSettings().bgColor;
        }
        setBgColor: function(color) {
            var settings = _retrieveSettings();
            settings.bgColor = color;
            _saveSettings(settings);
        }
    }
}]);

Then use it in your controller:

myApp.controller('MyCtrl', [$scope, SettingsFactory, function($scope, SettingsFactory) {

    $scope.settings = SettingsFactory.get(); // get settings including bgColor

    $scope.onBgColorChange = function(color) {
        SettingsFactory.setBgColor(color);
    }
}]);