生成随机字符串 ​

function randomString(length) {
  let chars =
    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz".split("");

  if (!length) {
    length = Math.floor(Math.random() * chars.length);
  }

  let str = "";
  for (let i = 0; i < length; i++) {
    str += chars[Math.floor(Math.random() * chars.length)];
  }
  return str;
}

/* examples */

// generate a random string of random length
randomString();

// generate a random string of length 8
randomString(8);

function randomString(length) {
  let chars =
    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz".split("");

  if (!length) {
    length = Math.floor(Math.random() * chars.length);
  }

  let str = "";
  for (let i = 0; i < length; i++) {
    str += chars[Math.floor(Math.random() * chars.length)];
  }
  return str;
}

/* examples */

// generate a random string of random length
randomString();

// generate a random string of length 8
randomString(8);