tidak bisa hapus data di php

mau delete data tapi kok dia nya gak mau ya padahal semuanya udah bener nih bang. ada solusi gak? mau ngapus data pakan burung perkutut tapi setelah diklik yes kok tidak berubah ya?

setelah diklik ok

barang.php [spoiler=]

<?php include 'header.php'; ?>

<h3><span class="glyphicon glyphicon-briefcase"></span>  Data Barang</h3>
<button style="margin-bottom:20px" data-toggle="modal" data-target="#myModal" class="btn btn-info col-md-2"><span class="glyphicon glyphicon-plus"></span>Tambah Barang</button>
<br/>
<br/>

<?php
$periksa=mysqli_query($connect, "select * from barang where jumlah <=3");
while($q=mysqli_fetch_array($periksa)){
	if($q['jumlah']<=3){
		?>
		<script>
			$(document).ready(function(){
				$('#pesan_sedia').css("color","red");
				$('#pesan_sedia').append("<span class='glyphicon glyphicon-asterisk'></span>");
			});
		</script>
		<?php
		echo "<div style='padding:5px' class='alert alert-warning'><span class='glyphicon glyphicon-info-sign'></span> Stok  <a style='color:red'>". $q['nama']."</a> yang tersisa sudah kurang dari 3 . silahkan pesan lagi !!</div>";
	}
}
?>
<?php
$per_hal=10;
$jumlah_record=mysqli_query($connect,"SELECT COUNT(*) from barang");
list($jum) = mysqli_fetch_row($jumlah_record);
echo $jum;
$halaman=ceil($jum / $per_hal);
$page = (isset($_GET['page'])) ? (int)$_GET['page'] : 1;
$start = ($page - 1) * $per_hal;;
?>
<div class="table">
	<table class="col-md-2">
		<tr>
			<td>Jumlah Record</td>
			<td><?php echo $jum; ?></td>
		</tr>
		<tr>
			<td>Jumlah Halaman</td>
			<td><?php echo $halaman; ?></td>
		</tr>
	</table>
	<a style="margin-bottom:10px" href="lap_barang.php" target="_blank" class="btn btn-default pull-right"><span class='glyphicon glyphicon-print'></span>  Cetak Data Barang</a><br>
</div>
<form action="cari_act.php" method="get">
	<div class="input-group col-md-5 col-md-offset-7">
		<span class="input-group-addon" id="basic-addon1"><span class="glyphicon glyphicon-search"></span></span>
		<input type="text" class="form-control" placeholder="Cari barang di sini .." aria-describedby="basic-addon1" name="cari">
	</div>
</form>
<br/>
<table class="table">
	<tr>
		<th>No</th>
		<th>Kode Barang</th>
		<th>Nama Barang</th>
		<th>Harga Jual</th>
		<th>Jumlah</th>
		<!-- <th class="col-md-1">Sisa</th>		 -->
		<th>Opsi</th>
	</tr>
	<?php
	if(isset($_GET['cari'])){
		$cari=mysqli_real_escape_string($connect,$_GET['cari']);
		$brg=mysqli_query($connect, "select * from barang where nama like '$cari' or jenis like '$cari'");
	}else{
		$brg=mysqli_query($connect, "select * from barang limit $start, $per_hal");
	}
	$no=1;
	while($b=mysqli_fetch_array($brg)){

		?>
		<tr>
			<td><?php echo $no++ ?></td>
			<td><?php echo $b['kode'] ?></td>
			<td><?php echo $b['nama'] ?></td>
			<td>Rp.<?php echo number_format($b['harga']) ?>,-</td>
			<td><?php echo $b['jumlah'] ?></td>
			<td>
				<a href="det_barang.php?id=<?php echo $b['id']; ?>" class="btn btn-info">Detail</a>
				<a href="edit.php?id=<?php echo $b['id']; ?>" class="btn btn-warning">Edit</a>
				<a onclick="if(confirm('Apakah anda yakin ingin menghapus data ini ??')){ location.href='hapus.php?id=<?php echo $b['id']; ?>' }" class="btn btn-danger">Hapus</a>
			</td>
		</tr>
		<?php
	}
	?>
	<tr>
		<td colspan="4">Total Modal</td>
		<td>
		<?php

			$x=mysqli_query($connect, "select sum(modal) as total from barang");
			$xx=mysqli_fetch_array($x);
			echo "<b> Rp.". number_format($xx['total']).",-</b>";
		?>
		</td>
	</tr>
</table>
<ul class="pagination">
			<?php
			for($x=1;$x<=$halaman;$x++){
				?>
				<li><a href="?page=<?php echo $x ?>"><?php echo $x ?></a></li>
				<?php
			}
			?>
		</ul>
<!-- modal input -->
<div id="myModal" class="modal fade">
	<div class="modal-dialog">
		<div class="modal-content">
			<div class="modal-header">
				<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
				<h4 class="modal-title">Tambah Barang Baru</h4>
			</div>
			<div class="modal-body">
				<form action="tmb_brg_act.php" method="post">
					<div class="form-group">
						<label>Kode Barang</label>
						<input name="kode" type="text" class="form-control" placeholder="Kode Barang .." required>
					</div>
					<div class="form-group">
						<label>Nama Barang</label>
						<input name="nama" type="text" class="form-control" placeholder="Nama Barang .." required>
					</div>
					<div class="form-group">
						<label>Jenis Barang</label>
						<input name="jenis" type="text" class="form-control" placeholder="Jenis Barang .." required>
					</div>
					<div class="form-group">
						<label>Harga Modal</label>
						<input name="modal" type="text" class="form-control" placeholder="Modal per unit" required>
					</div>
					<div class="form-group">
						<label>Harga Jual</label>
						<input name="harga" type="text" class="form-control" placeholder="Harga Jual per unit" required>
					</div>
					<div class="form-group">
						<label>Jumlah</label>
						<input name="jumlah" type="text" class="form-control" placeholder="Jumlah" required>
					</div>

				</div>
				<div class="modal-footer">
					<button type="button" class="btn btn-default" data-dismiss="modal">Batal</button>
					<input type="submit" class="btn btn-primary" value="Simpan">
				</div>
			</form>
		</div>
	</div>
</div>

<?php
include 'footer.php';

?>

[/spoiler]

hapus.php [spoiler=]

<?php
include 'config.php';
$id=$_GET['id'];
mysqli_query("delete from barang where id='$id'");
header("location:barang.php");

?>

[/spoiler]