带警报的删除按钮在php中不起作用

Question

If i click delete button, then ask permission from me for delete but after clicking OK not delete. From my code id for delete not get. In my browser search box show :

localhost/new/tree1/view_tree.php?id=

For getting id code is given below:

<?php
    include('connect.php');
    $result = mysql_query("SELECT * FROM descriptionoftree WHERE vis=0 order by scientificname");
    while($row = mysql_fetch_array($result))
        {
            echo '<tr>';
            echo '<td >'.$row['scientificname'].'</td>';
            echo '<td>'.$row['english_name'].'</div></td>';
            echo '<td>'.$row['banglaname'].'</div></td>';
            echo '<td>'.$row['groupname'].'</div></td>';
            echo '<td><a href="update_tree.php? id='.$row['id'].'" title="Click To Update"><strong>Update</strong></a></td>';
 ?>
    <td><a href="view_tree.php?id=<?php $row['id']?>
     "onclick="return confirm('Are you sure you want to delete?')"<strong>Delete </strong></a></td>
    <?php
        echo '</tr>';
        }   
        ?>

For deleterow code is given below:

if(isset($_GET['id']))
   {
     $cid=$_GET['id'];
     $sql=mysql_query("DELETE descriptionoftree WHERE id='$cid'");
   }

Answer 1

You're not echoing your variable here.

                                   vvv
<td><a href="view_tree.php?id=<?php $row['id']?>

Add an echo

<td><a href="view_tree.php?id=<?php echo $row['id']?>

Or use short echo tag

<td><a href="view_tree.php?id=<?= $row['id'] ?>

Also, your delete query is wrong. You're missing FROM.

Should be this:

$sql=mysql_query("DELETE FROM descriptionoftree WHERE id='$cid'");

Also try reading up on SQL Injections, How can I prevent SQL injection in PHP?

Your current code is vulnerable.