批量生成 UUID：v4 随机版与 v7 时间排序版（适合数据库主键），可切换大写、去连字符，一次最多 500 个；下方还能校验任意 UUID 的格式与版本。全部用浏览器加密随机数本地生成。Generate UUIDs in bulk: v4 (random) and v7 (time-ordered — great for database keys), with uppercase and hyphen options, up to 500 at once. A validator below checks any UUID's format and version. All generated locally with cryptographic randomness.
v4 与 v7 怎么选：普通场景用 v4 就够；如果拿 UUID 当数据库自增式主键，v7 按时间递增，索引友好得多，是这几年的新趋势（RFC 9562）。v4 or v7? v4 is fine for general use. If the UUID is a database primary key, v7 increases with time and is far friendlier to indexes — the modern choice (RFC 9562).