And also here's my code. I don't know exactly what happened to it. I hope someone will help me with this. Thank you in advance. :(
<!--Update-->
<?php
include "config.php";
include "header.php";
if(isset($_GET['u'])):
if(isset($_POST['bts'])):
$stmt = $mysqli->prepare("UPDATE personal SET id_personal=?, name=?, date=?, datepaid=?, amount=? WHERE id_personal=?");
$stmt->bind_param('sssss', $id, $en, $date, $dp, $amnt);
$id = $_POST['id'];
$en = $_POST['en'];
$date = $_POST['date'];
$dp = $_POST['dp'];
$amnt = $_POST['amnt'];
if($stmt->execute()):
echo "<script>location.href='index.php'</script>";
else:
echo "<script>alert('".$stmt->error."')</script>";
endif;
endif;
$res = $mysqli->query("SELECT * FROM personal WHERE id_personal=".$_GET['u']);
$row = $res->fetch_assoc();
?>