Extending ngModel

ngModelExtention

app.directive('ngModel', ['$timeout',function($timeout) {
    return {
        require: 'ngModel',
        restrict: 'A',
        link: function(scope, element, attrs, model) {
            var timer,
                delay = 1000;

            element.bind('keydown change input', function () {
                if (timer) {
                    $timeout.cancel(timer);
                }
                timer = $timeout(setVisited, delay);
            });

            element.bind('blur', setVisited);
            
            function setVisited() {
                model.$visited = true;
                timer = null;
            }
        }
    };
}]);