Senden verhindern, wenn das Eingabefeld leer ist

Question

Ich entwickle ein Kommentar-System für meine Social Media, aber Kommentare werden in die Datenbank eingefügt, auch wenn es leer ist.So will ich nichts passieren, wenn Kommentarfeld leer ist, möchte ich nicht echo jede Nachricht oder die Übermittlung des Kommentars.

Dies ist mein Code

<?php 
    // Get id of post 
    if(isset($_GET['post_id'])) { 

     $post_id = $_GET['post_id']; 
    } 

    $user_query = mysqli_query($con, "SELECT added_by, user_to FROM posts 
    WHERE id='post_id'"); 
    $row = mysqli_fetch_array($user_query); 

    $posted_to = $row['added_by']; 
    $user_to = $row['user_to']; 

    if(isset($_POST['postComment' . $post_id])) { 

     $post_body = $_POST['post_body']; 
     $post_body = mysqli_escape_string($con, $post_body); 
     $date_time_now = date("Y-m-d H:i:s"); 
    $insert_post = mysqli_query($con, "INSERT INTO comments VALUES ('', 
    '$post_body', '$userLoggedIn', '$posted_to', '$date_time_now', 'no', 
    '$post_id')"); 

    if($posted_to != $userLoggedIn) { 

     $notification = new Notification($con, $userLoggedIn); 
     $notification->insertNotification($post_id, $posted_to, "comment"); 
    } 

    if($user_to != 'none' && $user_to != $userLoggedIn) { 

     $notification = new Notification($con, $userLoggedIn); 
     $notification->insertNotification($post_id, $user_to, 
     "profile_comment"); 
    } 

    $get_commenters = mysqli_query($con, "SELECT * FROM comments WHERE 
    post_id='$post_id'"); 
    $notified_users = array(); 
    while($row = mysqli_fetch_array($get_commenters)) { 

     if($row['posted_by'] != $posted_to && $row['posted_by'] != $user_to 
      && $row['posted_by'] != $userLoggedIn && 
     !in_array($row['posted_by'], $notified_users)) { 

      $notification = new Notification($con, $userLoggedIn); 
      $notification->insertNotification($post_id, $row['posted_by'], 
      "comment_non_owner"); 

      array_push($notified_users, $row['posted_by']); 

     } 

    } 



    echo "<p>Comment Posted! </p>"; 
    } 

    ?> 

    <form action="comment_frame.php?post_id=<?php echo $post_id; ?>" 
    id="comment_form" name="postComment<?php echo $post_id; ?>" 
    method="POST"> 
    <textarea name="post_body" placeholder="Add a comment"></textarea> 
    <input type="submit" name="postComment<?php echo $post_id; ?>" 
    value="Comment"> 

</form> 

<!-- Load Comments --> 
<?php 
$get_comments = mysqli_query($con, "SELECT * FROM comments WHERE 
post_id='$post_id' ORDER BY id ASC"); 
$count = mysqli_num_rows($get_comments); 

if ($count != 0) { 

    while($comment = mysqli_fetch_array($get_comments)) { 

     $comment_body = $comment['post_body']; 
     $posted_to = $comment['posted_to']; 
     $posted_by = $comment['posted_by']; 
     $date_added = $comment['date_added']; 
     $removed = $comment['removed']; 

     //Timeframe 

     $date_time_now = date("Y-m-d H:i:s"); 
     $start_date = new DateTime($date_added); // Time of Post 
     $end_date = new DateTime($date_time_now); // Current time 
     $interval = $start_date->diff($end_date); // Difference between 
     dates 
     if($interval->y >= 1) { 
      if($interval == 1) 
       $time_message = $interval->y . " year ago"; // 1 year ago 
      else 
       $time_message = $interval->y . " years ago"; // 1+ year ago 
     } 
     else if ($interval-> m >= 1) { 

      if($interval->d == 0) { 
       $days = " ago"; 
      } 
      else if($interval->d == 1) { 
       $days = $interval->d . " days ago"; 
      } 
      else { 
       $days = $interval->d . " days ago"; 
      } 

      if($interval->m == 1) { 
       $time_message = $interval->m . " month". $days; 
      } 
      else { 

       $time_message = $interval->m . " months". $days; 
      } 
     } 
     else if($interval->d >=1) { 
      if($interval->d == 1) { 
       $time_message = "Yesterday"; 
      } 
      else { 
       $time_message = $interval->d . " days ago"; 
      } 
     } 
     else if($interval->h >= 1) { 
      if($interval->h == 1) { 
       $time_message = $interval->h . " hour ago"; 
      } 
      else { 
       $time_message = $interval->h . " hours ago"; 
      } 
     } 
     else if($interval->i >= 1) { 
      if($interval->i == 1) { 
       $time_message = $interval->i . " minute ago"; 
      } 
      else { 
       $time_message = $interval->i . " minutes ago"; 
      } 
     } 
     else { 
      if($interval->s < 30) { 
       $time_message = "Just now"; 
      } 
      else { 
       $time_message = $interval->s . " seconds ago"; 
      } 
     } 

     $user_obj = new User($con, $posted_by); 
     ?> 
     <div class="comment_section"> 
     <a href="<?php echo $posted_by?>" target="_parent"><img src="<?php 
     echo $user_obj->getProfilePic(); ?>" title="<?php echo $posted_by; 
     ?>" style="float:left;" height="30"></a> 
     <a href="<?php echo $posted_by?>" target="_parent"> <b><?php echo 
     $user_obj->getFirstAndLastName(); ?> </b> </a> 
     &nbsp;&nbsp;&nbsp;&nbsp; <?php echo $time_message . "<br>" . 
     $comment_body; ?> 
     <hr> 
     </div> 
     <?php 

    } 
    } 

    else { 

    echo "<center><br><br>No comments to show</center>"; 
    } 

    ?> 



    </body> 
    </html> 

Answer 1

dieses Attribut hinzufügen auf das richtige Eingabefeld: <input required: required;> dass es für Sie beheben soll :-)

http://w3c.github.io/html/sec-forms.html#the-required-attribute für weitere Informationen

Answer 2

eine Demo inklusive sehen unten. Das erste Formular wird eine Fehlermeldung anzeigen, wenn es gesendet wird - Attribut required - (die Sie wahrscheinlich nicht möchten) und das zweite Formular gibt keine Rückmeldung - Attribut required aber novalidate für das Formular.

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
 
<form> 
 
    <textarea required onsubmit="return false;"></textarea><br> 
 
    <input type="submit" value="submit"> 
 
</form><br><br> 
 

 
<form novalidate onsubmit="return false;"> 
 
    <textarea required></textarea><br> 
 
    <input type="submit" value="submit"> 
 
</form>