這是全局變量const navigation = document.getElementById('nav_list');const sections = document.querySelectorAll('section');const links = document.querySelectorAll('li')let navLinks = '';該函數用于創建導航。const navMaker = function() {    sections.forEach(section => {                const sectId = section.id;                const sectNav = section.dataset.name;                navLinks = navLinks + `<li><a class="links_menu" href="#${sectId}">${sectNav}</a>                 </li>`;    });    navigation.innerHTML = navLinks; } navMaker();該函數用于添加和刪除活動類這個常量用于訪問所有列表：const linkErrays = document.querySelectorAll('li');const level = (section) => {    return Math.floor(section.getBoundingClientRect().top)}const delateClass = (section) => {    section.classList.remove('active_section');}const addClass = (condition, section) => {    if (condition) {        section.classList.add('active_section');    }}這是當有人滾動時的類激活const classActivation = () => {      linkErrays.forEach(section => {        const elementLevel = level(section);        inviewport = () => elementLevel < 50  && elementLevel >= -650        delateClass(section);    addClass(inviewport(), section);  });}window.addEventListener('scroll', classActivation);