php用户密码修改的代码

<?php
     @session_start();
     require_once("../inc/ring_admin.php");
     require_once("../../inc/connect.php");
     require_once("../../admin/inc/function.php");
     ring_login();
     $pwd = get_value('pwd','post');
     $pwd2 = get_value('pwd2','post');
     $pwd3 = get_value('pwd3','post');
     $sql = "select * from gx_member  where m_pwd='".md5($pwd)."' and m_name='".$_SESSION['uid']."'";
    
      if( $pwd2!=$pwd3 || strlen( $pwd2)<6 || strlen( $pwd2)>12 ){
       alert('两次输入的新密码不正确,请重新输入!','');
      }else{  
       if(mysql_num_rows( mysql_query($sql) ) ){
        $sql="Update gx_member set m_pwd='".md5($pwd2)."' where m_name='".$_SESSION['uid']."'";
        mysql_query($sql) or die(mysql_error());
        alert('密码修改成功!','');
       }else{
        alert('旧密码不正确,请重新输入!','');
       }
      }    
?>