生成随机数

function generateRandomNumber() {
  var randomNumber = Math.floor(Math.random() * 10000000000000000);
  var randomString = randomNumber.toString().padStart(16, '0');
  return randomString;
}

var randomNum = generateRandomNumber();
console.log(randomNum);

function generateRandomString() {
  var characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
  var randomString = '';
  for (var i = 0; i <16; i++) {
    var randomIndex = Math.floor(Math.random() * characters.length);
    randomString += characters.charAt(randomIndex);
  }
  return randomString;
}

var randomStr = generateRandomString();
console.log(randomStr);