Почему мои пользователи не могут удалить свой комментарий?

Question

Я создал сайт со страницей комментариев для пользователей, чтобы удалить комментарии, которые они загружают. Однако кнопка удаления комментария появляется, однако она не работает. Кто-нибудь может пролить свет на это для меня, пожалуйста?

<?php
    require_once("checklog.php");
    include_once("nihome_start_logged.php");
    require_once("nifunctions.php");?>

<div id="navigation">
<ul class="container">
    <li><a href='nihome.php'>Home</a></li>
    <li><a href="nihome.php#content"> Search for your service</a></li>
    <li><a href='nisalons.php' class='button'>Salons and Reviews</a></li>
     <li><a href='nichangepassword.php' class='button'>Change Password</a></li>
     <li><a href='nilogout.php' class='button'>Logout</a></li>
</ul>
</div>

<?php

    if (!$db_server){
            die("Unable to connect to MySQL: " . mysqli_connect_error($db_server));
            $db_status = "not connected";
    }else{
        //Capture form data, if anything was submitted
        if (isset($_GET['salonid']) and ($_GET['salonid'] != '')){
            $salonid = clean_string($db_server, $_GET['salonid']);

            //code to delete comments
            if($db_server){
                mysqli_select_db($db_server, $db_database);
                mysqli_query($db_server, "DELETE FROM comments WHERE username = '$username' and salonid = '$salonid' ");
                $message= "<p> Comment deleted </p>";   


            //If connected, get Salons from database and write out
            mysqli_select_db($db_server, $db_database);
            $query = "SELECT ID, salon_name, address, postcode, telephone, email, website FROM salon WHERE ID=$salonid";
            $result = mysqli_query($db_server, $query); 
            if (!$result) die("Query failed: " . mysqli_error($db_server));

            while($row = mysqli_fetch_array($result)){
                $str_result .= "<h2>" . $row[ 'salon_name'] . "</h2>";
                $str_result .= "<p>" . $row['address'] . "</p>";
                $str_result .= "<p>" . $row['postcode'] . "</p>";
                $str_result .= "<p>" . $row['telephone'] . "</p>";
                $str_result .= "<p>" . $row['email'] . "</p>";
                $str_result .= "<p>" . $row['website'] . "</p>";
            }
            }
            mysqli_free_result($result);
        }else{
            $str_result = "<h2>No salon selected</h2>";

        }

    }
    echo $str_result;
?>

<?php 

if(trim($_POST['submit']) == "Submit comment"){

    //Get any submitted comments and insert
    $comment = clean_string($db_server, $_POST['comment']);
    if ($comment != '') {
        $name=$_FILES['photo']['name'];
        if ($name == "") $error .= "<p class='error'>You must write a review and upload an image!</p>";
        $originalname=$_FILES['photo']['name'];
        $type=$_FILES['photo']['type'];
        if ($type=="image/jpeg")  $type=".jpeg"; //if true change 
        else if ($type=="image/jpg") $type=".jpg";// if not true check this one
        else if ($type=="image/png") $type=".png";
        $name=uniqid() . $type;

        $path="images/" . $name;
        $tempname=$_FILES['photo']['tmp_name'];
        $size=$_FILES['photo']['size'];
        //Error checking
        if ($size >1000000) $error .= "<p class='error'>Your image file is to big, it have to be less than 200 mb</p>";
        if ($error=="") {
            if (move_uploaded_file($tempname, $path)){

                $uploadquery="INSERT INTO comments (comment, imagename, salonID, userID) VALUES ('$comment', '$path', $salonid, ". $_SESSION['userID'].")";
                mysqli_query($db_server,$uploadquery) or die ("Insert failed " . mysqli_error($db_server) . " " . $uploadquery);
                $message= "<h2>Thanks for your comment!</h2><p>Your upload was succesful</p>";

            }
        }
    }

}

//Print out existing comment
$query = "SELECT * FROM comments JOIN users ON comments.userID = users.ID WHERE salonID=$salonid"; 
$result = mysqli_query($db_server, $query);
if (!$result) die("Database access failed: " . mysqli_error($db_server));
while ($row = mysqli_fetch_array($result)){

        if ($_SESSION['username'] == $row['username']){
            $deletecomment = "<input class='delete comment' type='submit' id='submit' name='submit' value='Delete comment'/>";
        }else{
            $deletecomment = " ";
        }
        $str_comments .= "<p><span class='comments'>" . $row['Username'] ." : " . $row['comment'] . "</span></p>";
        $str_comments .="<p><img src='" . $row['imagename'] ."'  /></p>";
        $str_comments .= $deletecomment ;
}


mysqli_free_result($result);

?>  
<div id="form">
<table><form id='review' action='salonpage.php?salonid=<?php echo $salonid; ?>' method='post' enctype='multipart/form-data'>
<th><h2> Do you want to review the service you recieved?</h2></th>
<tr><td><textarea name="comment" rows="6" cols="40">Write something here!</textarea></td></tr>
<tr><td><input type='file' name='photo' accept='image/jpg, image/jpeg, image/png'/></td></tr>
<br/>
<tr><td><input type='submit' id='submit' name='submit' value='Submit comment' /></td></tr>
</form></table>
<?php echo $error;
    echo $message;?></div>

<h2> Reviews and comments </h2>
<?php echo $str_comments; ?>
<?php mysqli_close($db_server); ?>

<div id='footer'>
<a href="privacy.php">Privacy Statement</a>
<a href="accessibility.php">Accessibility Statement</a>
</div>
<?php include_once("nihome_end.php"); ?>

Answer 1

Из своего кода вы использовали кнопку отправки формы для удаления записи - и она сохраняется в $str_comments,

Тебе нужно <form .....> <?php echo $str_comments ?> </form>

Потому что для отправки кнопки нужна форма, чтобы жить в.

Answer 2

#1 Я предлагаю вам начать использовать классы.

# 2, если вы используете mysqli(я расшифровываю), почему вы делаете вещи "по-старому"?

# 3 классный пример

$drop = new CLASS_NAME_GOES_HERE;
$drop->drop_comment($id,$un);

class CLASS_NAME_GOES_HERE {

private $con; // only access from this class and its children and dont need $ anymore
function __construct() { // constructor function
        $this->con = new mysqli(DB,DB_USER,DB_PASS,DB_NAME) or
                die('Cannot connect.');
}

function drop_comment($id,$un) {
    $sql= "DELETE FROM upload WHERE id = ? AND username = ?";

    if($try = $this->con->prepare($sql)) {
        $try->bind_param('ss', $id, $un);
        if($try->execute()) return true; 
    }
}//END FUNCTION
}//end class