云缴费平台双11优惠活动

// 使用懒加载技术优化页面加载速度
document.addEventListener("DOMContentLoaded", function() {
    const images = document.querySelectorAll("img.lazy");
    const observer = new IntersectionObserver((entries, observer) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                const img = entry.target;
                img.src = img.dataset.src;
                img.classList.remove("lazy");
                observer.unobserve(img);
            }
        });
    });
    images.forEach(img => {
        observer.observe(img);
    });
});

# 使用缓存减少数据库查询次数
from functools import lru_cache
import sqlite3

@lru_cache(maxsize=128)
def get_user_info(user_id):
    conn = sqlite3.connect('users.db')
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM users WHERE id=?", (user_id,))
    user_info = cursor.fetchone()
    conn.close()
    return user_info