function create_password($pw_length = 8 )
{
      $randpwd = ”;
      for ($i = 0; $i < $pw_length; $i++)
      {
            $randpwd .= chr(mt_rand(33, 126));
      }
      return $randpwd;
}// 调用该函数，传递长度参数$pw_length = 6
echo create_password(6);

function generate_password( $length = 8 ) {
      // 密码字符集，可任意添加你需要的字符
$chars = ‘abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()-_ []{}<>~`+=,.;:/?|’;$password = ”;
      for ( $i = 0; $i < $length; $i++ )
      {
            // 这里提供两种字符获取方式
            // 第一种是使用 substr 截取$chars中的任意一位字符；
            // 第二种是取字符数组 $chars 的任意元素
            // $password .= substr($chars, mt_rand(0, strlen($chars) – 1), 1);
            $password .= $chars[ mt_rand(0, strlen($chars) - 1) ];
      }return $password;
}

function make_password( $length = 8 )
{
      // 密码字符集，可任意添加你需要的字符
      $chars = array(‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’, ‘g’, ‘h’,
      ‘i’, ‘j’, ‘k’, ‘l’,'m’, ‘n’, ‘o’, ‘p’, ‘q’, ‘r’, ‘s’,
      ‘t’, ‘u’, ‘v’, ‘w’, ‘x’, ‘y’,'z’, ‘A’, ‘B’, ‘C’, ‘D’,
      ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’, ‘K’, ‘L’,'M’, ‘N’, ‘O’,
      ‘P’, ‘Q’, ‘R’, ‘S’, ‘T’, ‘U’, ‘V’, ‘W’, ‘X’, ‘Y’,'Z’,
      ’0′, ’1′, ’2′, ’3′, ’4′, ’5′, ’6′, ’7′, ’8′, ’9′, ‘!’,
      ‘@’,'#’, ‘$’, ‘%’, ‘^’, ‘&’, ‘*’, ‘(‘, ‘)’, ‘-’, ‘_’,
‘[', ']‘, ‘{‘, ‘}’, ‘’, ‘~’, ‘`’, ‘+’, ‘=’, ‘,’,
      ‘.’, ‘;’, ‘:’, ‘/’, ‘?’, ‘|’);// 在 $chars 中随机取 $length 个数组元素键名
      $keys = array_rand($chars, $length);$password = ”;
      for($i = 0; $i < $length; $i++)
      {
            // 将 $length 个数组元素连接成字符串
            $password .= $chars[$keys[$i]];
      }return $password;
}

 <?php
function getmicrotime()
{
       list($usec, $sec) = explode(” “,microtime());
       return ((float)$usec + (float)$sec);
}// 记录开始时间
$time_start = getmicrotime();// 这里放要执行的PHP代码，如:
// echo create_password(6);// 记录结束时间
$time_end = getmicrotime();
$time = $time_end – $time_start;// 输出运行总时间
echo “执行时间 $time seconds”;
?>