code: function prepend(element, content) {
    if (isString(content)) {
      return element.insertAdjacentHTML('afterBegin', content);
    } else {
      return element.insertBefore(normalizeContent(content), element.firstChild);
    }
  }
docs: prepend
  @param {Element} element
  @param {String|Node|NodeList|Array<Node>} content