// 生成随机字符串的函数 function generateRandomString(length) { const characters = 'abcdefghijklmnopqrstuvwxyz0123456789'; let result = ''; for (let i = 0; i < length; i++) { result += characters.charAt(Math.floor(Math.random() * characters.length)); } return result; } // 为所有 div 元素添加随机字符串 document.querySelectorAll('div').forEach(div => { const randomString = generateRandomString(3); // 生成3个字符的随机字符串 div.classList.add(randomString); });