用这个可以来验证用户和生成随机密码--teaman <?         //----------------------------------------------------         // Function GetSID()         //         // Parameters : $nSize number of caracters, default 24         // Return value : 24 caracters string         //         // Description : This function returns a random string         // of 24 caracters that can be used to identify users         // on your web site in a more secure way. You can also           // use this function to generate passwords.         //----------------------------------------------------         function GetSID ($nSize=24) {                           // Randomize             mt_srand ((double) microtime() * 1000000);             for ($i=1; $i<=$nSize; $i++) {                                   // if you wish to add numbers in your string,                   // uncomment the two lines that are commented                 // in the if statement                 $nRandom = mt_rand(1,30);                 if ($nRandom <= 10) {                     // Uppercase letters                     $sessionID .= chr(mt_rand(65,90));             //    } elseif ($nRandom <= 20) {             //        $sessionID .= mt_rand(0,9);                 } else {                     // Lowercase letters                     $sessionID .= chr(mt_rand(97,122));                 }                               }                      return $sessionID;         }         // Test the function           echo GetSID(16);     ?>