PHP MD5加密 注册登陆（原生）

逻辑层

    <?php
/*
 * @Description: 登陆验证 模块
 * @Author: Fore-Zhang
 * @Date: 2020-03-29 09:28:41
 * @LastEditTime: 2020-03-29 21:45:50
 * @LastEditors: 项目组长
 */
    /* 登陆conn.php*/
    error_reporting(0);
    include '../db/db.php';
    $username=$_POST['username'];
    $password=md5($_POST['password']);
    echo $password;
    $sql="select * from admin where username='".$username."'";
    $res=mysql_query($sql);
    if($_POST['dl']=="登录"){
        if($row=mysql_fetch_array($res)){
            echo '/n';
            echo $row['password'];  
        if($row['password']==$password){
            // $_SESSION['username']=$row['username'];
            header("location:index.php");
        exit();
        }else{
        echo "<script> alert('密码不正确')</script>";
        }
        }else{
        echo "<script> alert('用户名不存在')</script>";
        }
}
?>

<?php
/*
 * @Description: 注册模块
 * @Author: Fore-Zhang
 * @Date: 2020-03-29 09:28:41
 * @LastEditTime: 2020-03-29 21:45:50
 * @LastEditors: 项目组长
 */
  /* 注册 connLogin.php*/
    header("Content-type: text/html; charset=utf-8");
        $username = $_POST['username'];
        $password = $_POST['password'];
        $hashpwd = md5($password);
        echo "<script>console.log($hashpwd)</script>";
        $repassword = $_POST['repassword'];
        if ($username == ''){
            echo '<script>alert("请输入用户名！");history.go(-1);</script>';
            exit(0);
        }
        if ($password == ''){
            echo '<script>alert("请输入密码");history.go(-1);</script>';
            exit(0);
        }
        if ($password != $repassword){
            echo '<script>alert("密码与确认密码应该一致");history.go(-1);</script>';
            exit(0);
        }
        if($password == $repassword){
            $conn = new mysqli('localhost','root','971023','as');
            if ($conn->connect_error){
                echo '数据库连接失败！';
                exit(0);
            }else {
                $sql = "select username from admin where username = '$_POST[username]'";
                $result = $conn->query($sql);
                if (!$result) {
                   printf("Error: %s\n", mysqli_error($conn));
                     exit();
                    }
                $number = mysqli_num_rows($result);
                if ($number) {
                    echo '<script>alert("用户名已经存在");history.go(-1);</script>';
                } else {
                    $sql_insert = "insert into admin (username,password) values('$_POST[username]','$hashpwd')";
                    $res_insert = $conn->query($sql_insert);
                    if ($res_insert) {
                        echo '<script>window.location="login.php";</script>';
                    } else {
                        echo "<script>alert('系统繁忙，请稍候！');</script>";
                    }
                }
            }
        }else{
            echo "<script>alert('提交未成功！'); history.go(-1);</script>";
        }
?>

显示层

login.php 登陆页 
<form action="connte.php" method="post">
                    <div class="form-group">
                      <input type="text" class="form-control" id="username" name="username" value="" placeholder="用户名"  aria-describedby="emailHelp" >
                      
                    </div>
                    <div class="form-group">
                      <input type="password" class="form-control"  id="password" name="password" value="" placeholder="密码">
                    </div>
                      <div class="form-check"
                      <label class="switch">
                      <input type="checkbox">
                      <span class="slider round"></span>
                    </label>
                      <label class="form-check-label" for="exampleCheck1">记住选项 </label>
                      <label class="forgot-password" ><a href="register.html">注册<a></label>
                    </div>
                    <br>
<button type="submit"  value="登录" name="dl"  class="btn btn-lg btn-block btn-success">登陆 </button>
                  </form>
--------------
注册页
      <!-- Loging form -->
          <form action="conn.php" method="post">
            <div class="form-group">
              <input type="text" class="form-control" id="username" name="username" value="" placeholder="用户名"
                aria-describedby="emailHelp">

            </div>
            <div class="form-group">
              <input type="password" class="form-control" id="password" name="password" value="" placeholder="密码">
            </div>

            <div class="form-group">
              <input type="password" class="form-control" id="repassword" name="repassword" value="" placeholder="确认密码">
            </div>
            <div class="form-check">

              <label class="switch">
                <input type="checkbox">
                <span class="slider round"></span>
              </label>
              <label class="form-check-label" for="exampleCheck1">记住选项 </label>

              <label class="forgot-password"><a href="login.php">注册<a></label>

            </div>

            <br>
            <button type="submit" value="登录" name="dl" class="btn btn-lg btn-block btn-success">登陆 </button>
          </form>
          <!-- End Loging form -->