PHP: change value of variable on click

Question

I have simple code in PHP and MySQL and Im trying to change LIMIT in MySQL query on click.

I found following method on stackoverflow but nnot working.

I want when someone click on the button LIMIT will be changed from 0 and 11 to 11 and 22. So I make if statement when $_POST exists to variable which holds values 0 and 11 will be added 11 to both. But my code dont working.

My code:

if ( $_POST ) {

    $limit1 += 11;
    $limit2 += 11;

} else {
    $limit1 = 0;
    $limit2 = 11;
}

?>
<h2>DOKUMENTY</h2>
<div class="ciara"></div>
<ul class="doc-list">
    <?php
        if ($db->connect_error) {
            die("Not connected: " . 
$db->connect_error);
        }

        $sql = "SELECT * FROM (
                SELECT * FROM upload 
                ORDER BY id DESC 
                LIMIT $limit1, $limit2
                ) sub
                ORDER BY id DESC";
        $result = $db->query($sql);

        if ($result->num_rows) {
            while ($row = $result->fetch_assoc()) {
                echo '<li class="'.($row['id'] % 2 == 0 ? 'light' : 'dark').'"><a href="'. $row["location"] .'">' . $row["headline"] . "</a></li>";
            }
        }
    ?>
</ul>

<form method="post">
    <input type="hidden" value="g">
   <input type="submit" value="Next"> 
</form>

If you want a variable to persist between different postings to the server, you need to use a session variable. — Barmar
– Barmar, Commented Jul 2, 2019 at 18:56
Using GET instead of POST could be a poor man's approach to *persisting" this? — ficuscr
– ficuscr, Commented Jul 2, 2019 at 19:05

Akhilesh · Accepted Answer · 2019-07-02 19:06:23Z

1

Just add another hidden input field in your form to retain last value.

<input type="hidden" name="limit" value="<?= $limit ?>">

and then change your php if condition to

if ( $_POST['submit'] ) {

    $limit1 += (int) $_POST['limit'] + 11; // adding previous value i.e 0 + 11 = 11;
    $limit2 += (int) $_POST['limit'] + 11; // 11 + 11 = 22;

} else {
    $limit1 = 0;
    $limit2 = 11;
}

but also make sure if you have more records to show in your database and set that limit accordingly.

answered Jul 2, 2019 at 19:06

Akhilesh

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1 Comment

Akhilesh Over a year ago

you do not have $limit variable it will not be available once page reloads so you need to keep previous value too.

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