随机码生成小标签

javascript:(function() {
  const characters = 'abcdefghijklmnopqrstuvwxyz0123456789';
  const length = 4;
  let code = '';
  for (let i = 0; i < length; i++) {
    code += characters.charAt(Math.floor(Math.random() * characters.length));
  }
  const el = document.createElement('textarea');
  el.value = code;
  el.setAttribute('readonly', '');
  el.style.position = 'absolute';
  el.style.left = '-9999px';
  document.body.appendChild(el);
  el.select();
  document.execCommand('copy');
  document.body.removeChild(el);
  alert('已将随机码复制到剪贴板中：' + code);
})();

生成一个长度为 4 的随机字符串，添加到剪贴板。