建立login.php檔案

此頁面完成的功能如下

##程式碼如下

<?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='login.html'</script>";
            exit;
        }
        else{
            $_SESSION['username']=$row['username'];
            $_SESSION['id']=$row['id'];
            echo "<script>alert('登錄成功');location='first.html'</script>";
        }
    }else{
        echo "<script>alert('您輸入的用戶名不存在');location='login.html'</script>";
        exit;
    };

#