1//show effect
2this.element.css({visibility:"visible", opacity: 0.0}).animate({opacity: 1.0}, 300, () => {
3  this.element.removeClass('hidden');
4});
5//hidden effect
6this.element.animate({opacity: 0.0}, 200, () => {
7  this.element.css("visibility","hidden");
8  this.element.addClass('hidden');
9});