PHP development login page PHP page

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");
$link = mysqli_connect('localhost','root','root','login');  //链接数据库
 mysqli_set_charset($link ,'utf8'); //设定字符集 

$name=$_POST['username'];

$pwd=$_POST['password'];

$yzm=$_POST['yzm'];

    if($name==''){
        echo "<script>alert('请输入用户名');location='" . $_SERVER['HTTP_REFERER'] . "'</script>";
        exit;
    }
    if($pwd==''){

        echo "<script>alert('请输入密码');location='" . $_SERVER['HTTP_REFERER'] . "'</script>";
        exit;

    }

    if($yzm!=$_SESSION['VCODE']){

        echo"<script>alert('你的验证码不正确，请重新输入');location='".$_SERVER['HTTP_REFERER']. "'</script>";
        exit;

    }


    $sql_select="select id,username,password from user where username= ?";      //从数据库查询信息
    $stmt=mysqli_prepare($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('密码错误，请重新输入');location.href='login.html'</script>";
            exit;
        }
        else{
            $_SESSION['username']=$row['username'];
            $_SESSION['id']=$row['id'];
            echo "<script>alert('登录成功');location.href='first.html'</script>";
        }

    }else{
        echo "<script>alert('您输入的用户名不存在');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