code

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Bootstrap Example</title>
  <meta charset="utf-8">
    <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
  <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
</head>

<body>


<div class="container">
    <div class="row">
        <div class="col-sm-5"">
        <h2 style="color:#396;">Tuskar</h2>
        </div>
        <div class="col-sm-5 pull-right text-right"">
            <h3>Leading the Future, semakin di depan</h3>
        </div>
    </div>
</div>

<nav class="navbar navbar-inverse navbar-static-top" >
    <div class="container">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
        </div>
        <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
            <ul class="nav navbar-nav navbar-right">
                <li><a href="testing.php">Home</a></li>
                <li class="dropdown">
                  <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Database <span class="caret"></span></a>
                  <ul class="dropdown-menu">
                    <li><a href="#">Penjualan</a></li>
                    <li><a href="#">Another action</a></li>
                    <li><a href="#">Something else here</a></li>
                    <li role="separator" class="divider"></li>
                    <li><a href="#">Separated link</a></li>
                    <li role="separator" class="divider"></li>
                    <li><a href="#">One more separated link</a></li>
                  </ul>
                </li>
                <li><a href="#">Contact</a></li>
            </ul>
        </div>
    </div>
</nav>

<div class="container">
  <h2>Input Penjualan</h2>
  <p>Masukkan tanggal order, nama pembeli dan email. </p>
</div>

<?php

    $servername = "localhost";
    $username = "duriancub";
    $password = "1234";
    $dbname = "penjualan";

    // Create connection
    $conn = new mysqli($servername, $username, $password, $dbname);
    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }
    if ($_SERVER["REQUEST_METHOD"] == "POST") {

      $nama = $_POST['nama'];
      $tanggal = $_POST['tanggal'];
      $email = $_POST['email'];


      $sql = "INSERT INTO `order` (nama_pembeli, tanggal, email) VALUES ('$nama','$tanggal','$email')";

     if ($conn->query($sql) === TRUE) {
        echo '<div class="container">
                <div class="alert alert-success">
                <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                <strong>Success!</strong> Data berhasil di kirim.
                </div>
              </div>';
    }
    else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
    $conn->close();
}
?>


<div class="container">
  <form method="post"   class="form-horizontal" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
    <div class="form-group">
      <label class="col-sm-2 control-label" >Nama Pembeli:</label>
      <div class="col-sm-10">
      <input type="text" class="form-control" name="nama">
      </div>
    </div>
    <div class="form-group">
      <label class="col-sm-2 control-label" >Tanggal :</label>
      <div class="col-sm-10">
      <input type="text" class="form-control" name="tanggal">
      </div>
    </div>
    <div class="form-group">
      <label class="col-sm-2 control-label" >Email:</label>
      <div class="col-sm-10">
      <input type="text" class="form-control" name="email">
      </div>
    </div>
    <input type="submit" name="submit" class="btn-lg btn-primary btn-block" value="KIRIM"></input>
  </form>

</div>


</body>
</html>