function Animator(element) {
    this._element = element;
    this._animation = null;
    this._duration = 0;
    this._easing = '';
    this._callback = null;
    this._props = [];
    this._values = [];
    this._isDestroyed = false;
    this._onFinish = this._onFinish.bind(this);
  }
Item animation handler powered by Web Animations API.

@class
@param {HTMLElement} element