constructor(ctx, iframes = true, exclude = [], iframesTimeout = 5000) {
    /**
     * The context of the instance. Either a DOM element, an array of DOM
     * elements, a NodeList or a selector
     * @type {HTMLElement|HTMLElement[]|NodeList|string}
     * @access protected
     */
    this.ctx = ctx;
    /**
     * Boolean indicating if iframe support is enabled
     * @type {boolean}
     * @access protected
     */
    this.iframes = iframes;
    /**
     * An array containing exclusion selectors for iframes
     * @type {string[]}
     */
    this.exclude = exclude;
    /**
     * The maximum ms to wait for a load event before skipping an iframe
     * @type {number}
     */
    this.iframesTimeout = iframesTimeout;
  }
@param {HTMLElement|HTMLElement[]|NodeList|string} ctx - The context DOM
element, an array of DOM elements, a NodeList or a selector
@param {boolean} [iframes=true] - A boolean indicating if iframes should
be handled
@param {string[]} [exclude=[]] - An array containing exclusion selectors
for iframes
@param {number} [iframesTimeout=5000] - A number indicating the ms to
wait before an iframe should be skipped, in case the load event isn't
fired. This also applies if the user is offline and the resource of the
iframe is online (either by the browsers "offline" mode or because
there's no internet connection)