<ul>
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
<li>5</li>
</ul>let menu = document.querySelector("ul");
  let menuItems = menu.querySelectorAll("li");
  for (let item of menuItems) {
    item.addEventListener("click", myfunction);
  } 
  
  const siblings = Array.prototype.filter.call(
  this.parentNode.children,
  n => n !== this
);const siblings = [];
for (let el = this; (el = el.previousElementSibling); siblings.unshift(el)) ;
for (let el = this; (el = el.nextElementSibling); siblings.push(el)) ;