需要注意这些点：

• 位置记录： 监听滚动事件，记录滚动位置
• 存储介质： 使用浏览器存储方案持久化数据
• 位置恢复： 页面加载时读取存储数据并定位

方案1：滚动监听 + localStorage

// 记录滚动位置
window.addEventListener('scroll', throttle(function() {
const scrollY = window.scrollY || document.documentElement.scrollTop;
  localStorage.setItem('lastScrollPosition', scrollY);
}, 100)); // 节流函数降低性能消耗

// 恢复位置
window.addEventListener('DOMContentLoaded', () => {
const savedPosition = localStorage.getItem('lastScrollPosition');
if (savedPosition) {
    window.scrollTo(0, parseInt(savedPosition));
  }
});

// 节流函数实现
function throttle(fn, delay) {
let lastCall = 0;
returnfunction(...args) {
    const now = Date.now();
    if (now - lastCall < delay) return;
    lastCall = now;
    return fn.apply(this, args);
  };
}

方案2：锚点标记 +URL参数

// 记录锚点元素ID
document.querySelectorAll('.section').forEach(el => {
  el.addEventListener('click', () => {
    const activeId = el.id;
    history.replaceState(null, '', `#${activeId}`);
  });
});

// 恢复滚动
window.addEventListener('load', () => {
const hash = window.location.hash.slice(1);
if (hash) {
    const target = document.getElementById(hash);
    target?.scrollIntoView({ behavior: 'smooth' });
  }
});

方案3：Intersection Observer API

// 记录最近可见的元素
const observer = new IntersectionObserver(entries => {
  entries.forEach(entry => {
    if (entry.isIntersecting) {
      const elementId = entry.target.id;
      localStorage.setItem('lastVisibleElement', elementId);
    }
  });
}, { threshold: 0.5 });

// 观察所有章节元素
document.querySelectorAll('.chapter').forEach(el => observer.observe(el));

// 恢复时滚动到最近可见元素
const lastElementId = localStorage.getItem('lastVisibleElement');
if (lastElementId) {
document.getElementById(lastElementId)?.scrollIntoView();
}

方案4：滚动位置预测（适用于动态加载内容）

let lastKnownPos = 0;
let ticking = false;

window.addEventListener('scroll', () => {
  lastKnownPos = window.scrollY;

if (!ticking) {
    window.requestAnimationFrame(() => {
      // 预测用户滚动方向
      const viewportHeight = window.innerHeight;
      const predictPosition = lastKnownPos + (viewportHeight * 0.3);
      
      localStorage.setItem('predictPos', predictPosition);
      ticking = false;
    });
    ticking = true;
  }
});

// 恢复时使用预测位置
const savedPos = localStorage.getItem('predictPos');
if (savedPos) {
window.scrollTo(0, savedPos);
}