Set a specific Time duration for page - php

Question

I would like to specify the duration of the display of a form. Suppose there is a variable with the value x=(10), whenever I call this page, the timer should be based on the current time and the form should be displayed for 10 minutes and after this time the form should be sent automatically.
<?php
include 'db_conn.php';
if (isset($_GET['id'])) {
$var=$_GET['id'];
$query="SELECT * FROM addquiz WHERE quz_id='$var' ";
$db=mysqli_query($conn,$query);
$res=mysqli_fetch_array($db);
$noquestions=$res['noquestion'];
$quiz=$res['title'];
}?>
<div class="container">
<form method="POST" class="form-horizontal" >
<div style="margin-left: 30%;"><b>Your Quiz: <?php echo $quiz;?></b>
<input type="text" name="user_name" placeholder="Enter Your Name" style="height: 30px; width: 30%;"></div>
<div class="row">
<div class="col-md-12">
<div class="panel" style="margin:5%">
<?php
$count=1;
$que="SELECT * FROM addques WHERE quz_id='$var'";
$dbd=mysqli_query($conn,$que);
while ($cmd=mysqli_fetch_array($dbd)) {
$quest=$cmd['qusname'];
$ans_id=$cmd['ans_id'];
$opt1=$cmd['qpta'];
$opt2=$cmd['optb'];
$opt3=$cmd['optc'];
$opt4=$cmd['optd'];
$answ=$cmd['answer'];?>
<b>Question <?php echo $count++;?> :<br><?php echo $quest;?></b><br><br>
<fieldset>
<input type="hidden" name="ansid[]" value="<?php echo $ans_id; ?>">
<input type="checkbox" name="ans[]" value="1"><?php echo $opt1;?><br><br>
<input type="checkbox" name="ans[]" value="2"><?php echo $opt2;?><br><br>
<input type="checkbox" name="ans[]" value="3"><?php echo $opt3;?><br><br>
<input type="checkbox" name="ans[]" value="4"><?php echo $opt4?><br><br><br>
</fieldset>
<?php } ?>
<button type="submit" name="submit" class="btn btn-primary">Submit</button>
</form>
<div class="button" style="margin-left: 60%;"> View Result </div>
</div>
</div>
</div>
<?php
$i=0;
if (isset($_POST['submit'])) {
$name=$_POST['user_name'];
while ( $i<$noquestions ) {
$query="INSERT INTO `result`( `quz_id`, `ans_id`, `answer`,`user_name`) VALUES('";
$query.=$var . "', '";
$query.=$_POST['ansid'][$i] . "', '";
$query.=$_POST['ans'][$i] . "', '";
$query.=$name . "' )";
$db=mysqli_query($conn,$query);
$i++;
}
}
?>

Answer 1

It depends on what you are trying to achieve.
As you say "at each visit of the page" it could be done like this with javascript:
window.onload = function () {
window.setTimeout(function () {
document.form.submit();
}, 5000);
};
Further you could set the timeout from your php variable and like the comment says above, you could validate the taken time on the server side with php to make sure no one is cheating.