code: function getHeight(el) {
    let styles = window.getComputedStyle(el);
    let height = el.offsetHeight;
    let borderTopWidth = parseFloat(styles.borderTopWidth);
    let borderBottomWidth = parseFloat(styles.borderBottomWidth);
    let paddingTop = parseFloat(styles.paddingTop);
    let paddingBottom = parseFloat(styles.paddingBottom);
    return height - borderBottomWidth - borderTopWidth - paddingTop - paddingBottom;
  }
docs: Replacement for jQuery $.height()
  Borrowed with thanks from https://github.com/nefe/You-Dont-Need-jQuery#2.2