navegaçao por tab

const tabMenu = document.querySelectorAll('.js-tabmenu li')
const tabContent = document.querySelectorAll('.js-content section');
if(tabMenu.length && tabContent.length){
    function activeTab(index){
    tabContent.forEach((section)=>{
        section.classList.remove('ativo');
       });
       tabContent[index].classList.add('ativo');
    }
    tabMenu.forEach((itemmenu,index)=>{
    itemmenu.addEventListener('click', ()=>{
        activeTab(index);
        });
    });
}