silakan coba

<?php
require_once "core/init.php";
require_once "view/header.php";


$articles = tampilkan();
if($articles===false){ die('error mysql:'.mysqli_error()); }



if (isset($_GET['cari'])) {
    $cari     = $_GET['cari'];
    $articles = hasil_cari($cari);
    if($articles===false){ die('error mysql:'.mysqli_error()); }
    # code...
}

?>

<form action="" method="get">
<input type="search" name="cari" placeholder="Search">

</form>

  <nav class="black " role="navigation">
    <div class="nav-wrapper container">
      <a id="logo-container" href="#" class="brand-logo">Logo</a>
      <ul class="right hide-on-med-and-down">
        <li><a href="index.php">Home</a></li>
         </ul>

      <ul id="nav-mobile" class="side-nav">
        <li><a href="index.php">Home</a></li>
      </ul>
      <a href="" data-activates="nav-mobile" class="button-collapse"><i class="material-icons">Content</i></a>
    </div>
  </nav>


<?php
while($row=mysqli_fetch_assoc($articles)):  ?>

<div class="each_article">
    <h3><a href="single.php?id=<?php echo $row['id'];?>"><?php echo $row['judul']; ?></a></h3>
        <p>
            <?php echo excerpt($row['isi']); ?>
        </p>
        <p class="waktu">Post : <?php echo $row['waktu']; ?></p>
        <p class="tag"> Tag : <?php echo $row['tag']; ?></p>
        <a href="edit.php?id=<?php echo  $row['id']; ?>">Edit</a>
        <a href="delete.php?id=<?php echo  $row['id']; ?>">Delete</a>

</div>
<?php endwhile; ?>


<?php
require_once "view/footer.php";
?>