Untitled

<?php
    session_start();
    $value1 = $value2 = $error1 = $error2 = '';

    if (isset($_POST['submit'])) {
            $value1 = $_POST['post1'];
            $value2 = $_POST['post2'];
            if (strlen($value1) < 8) {
                $error1 = 'minimum 8 characters';
            }
            if (!is_numeric($value2)) {
                $error2 = 'must be numeric';
            }
            if (empty($value1)) {
                $error1 = 'this field is required';
            }
            if (empty($value2)) {
                $error2 = 'this field is required';
            }
            if (empty($error1) && empty($error2)) {
                // insert your data;
                header('location: '. $_SERVER['PHP_SELF']);
            }
    }
?>
<DOCTYPE html>
<html>
<head><head>
<body>
    <form action="" method="POST">
        <input type="text" name="post1" value="<?= $value1; ?>" placeHolder="Minumum 8 Characters">
        <div class="error"><?= $error1; ?></div>
        <input type="text" name="post2" value="<?= $value2; ?>" placeHolder="Must Be Numeric Value">
        <div class="error"><?= $error2; ?></div>
        <input type="submit" name="submit" value="submit">
    </form>
</body>
</html>