function toggleCallout(this: HTMLElement) { const outerBlock = this.parentElement! outerBlock.classList.toggle(`is-collapsed`) const collapsed = outerBlock.classList.contains(`is-collapsed`) const height = collapsed ? this.scrollHeight : outerBlock.scrollHeight outerBlock.style.maxHeight = height + `px` } function setupCallout() { const collapsible = document.getElementsByClassName(`callout is-collapsible`) as HTMLCollectionOf for (const div of collapsible) { const title = div.firstElementChild if (title) { title.removeEventListener(`click`, toggleCallout) title.addEventListener(`click`, toggleCallout) const collapsed = div.classList.contains(`is-collapsed`) const height = collapsed ? title.scrollHeight : div.scrollHeight div.style.maxHeight = height + `px` } } } document.addEventListener(`nav`, setupCallout) window.addEventListener(`resize`, setupCallout)