minesweeper.directive('ngRightClick', function($parse) {
    return function(scope, element, attrs) {
        var fn = $parse(attrs.ngRightClick);
            element.bind('contextmenu', function(event) {
                scope.$apply(function() {
                    event.preventDefault();
                    fn(scope, {$event:event});
                });
        });
    };
});

如上程式碼，解釋說是自訂ngRightClick指令，但首先不能理解它的意思，再一個自訂指令不應該是下面這種形式嗎：

minesweeper.directive("mineGrid",function(){
    return {
        restrict:'E',
        replace:false,
        templateUrl:'./templates/mineGrid.html'
    }
});

求指教