Login page PHP page

We need to judge whether the user name and password we entered in the HTML form, as well as the verification code are consistent with The data in the database is the same. If it is different, relevant prompts will be given, as well as the page returned if the verification is passed... These functions are completed on our PHP page,

The code is as follows

<?php
session_start();
header("Content-type:text/html;charset=utf-8");
$link = mysqli_connect('localhost','root','root','login');  //鏈接數(shù)據(jù)庫
 mysqli_set_charset($link ,'utf8'); //設(shè)定字符集 

$name=$_POST['username'];

$pwd=$_POST['password'];

$yzm=$_POST['yzm'];

    if($name==''){
        echo "<script>alert('請輸入用戶名');location='" . $_SERVER['HTTP_REFERER'] . "'</script>";
        exit;
    }
    if($pwd==''){

        echo "<script>alert('請輸入密碼');location='" . $_SERVER['HTTP_REFERER'] . "'</script>";
        exit;

    }

    if($yzm!=$_SESSION['VCODE']){

        echo"<script>alert('你的驗證碼不正確，請重新輸入');location='".$_SERVER['HTTP_REFERER']. "'</script>";
        exit;

    }


    $sql_select="select id,username,password from user where username= ?";      //從數(shù)據(jù)庫查詢信息
    $stmt=mysqli_prepare($link,$sql_select);
    mysqli_stmt_bind_param($stmt,'s',$name);
    mysqli_stmt_execute($stmt);
    $result=mysqli_stmt_get_result($stmt);
    $row=mysqli_fetch_assoc($result);

    if($row){

        if($pwd !=$row['password'] || $name !=$row['username']){

            echo "<script>alert('密碼錯誤，請重新輸入');location.href='login.html'</script>";
            exit;
        }
        else{
            $_SESSION['username']=$row['username'];
            $_SESSION['id']=$row['id'];
            echo "<script>alert('登錄成功');location.href='first.html'</script>";
        }

    }else{
        echo "<script>alert('您輸入的用戶名不存在');location.href='login.html'</script>";
        exit;
    };

The above is the code where we judge the password, user name, and verification code, and give relevant prompt information.

But when we don’t have an account to log in, we need to register an account so that we can log in. The following chapters will show you how to create the registration page