数据访问（登录数据库查询内容在网页显示）

<form action="./loginchuli.php" method="post">

    <div>用户名：<input type="text" name="uid" /></div>

    <div>密码：<input type="password" name="pwd" /></div>

    <div><input type="submit" disabled="disabled" value="登录"
 
onclick="return check()" /></div>

</form>

$uid = $_POST["uid"];

$pwd = $_POST["pwd"];

$db = new MySQLi("localhost","root","123","mydb");

if(mysqli_connect_error()){

    die("连接失败！");

}

$sql = "select pwd from users where uid=‘{$uid}‘";

$reslut = $db->query($sql);

$arr = $reslut->fetch_row();

if($arr[0]==$pwd && !empty($pwd)){

    echo "<script>window.location.href=‘main.php‘</script>";

}else{

    header("location:login.php");

}