Passing a variable in $_POST parameters not working in PHP? - php

Question

I am displaying images from a database, each image has a comment box that contains a form and a submit button; the submit button has the name of the image that is displayed. Ex. if the image name is flowers.jpg, the name for the submit button is set to flowers.jpg. (I did string replace though, so in my code it would be set to flowersjpg) The names are added to the submit button with no problem at all. Because I have several images, I wanted to pass $row['image'] (image name) into $_POST[ ] parameters for an isset() function but it is not working. - All the code is in one document
$result = mysqli_query($conn, "SELECT * FROM uploads ORDER BY timestamp DESC");
while($row = mysqli_fetch_array($result))
{
// Prints all the photos with a caption
echo "<div class='wrapper' name=".$row['image'].">";
echo "<div class='caption'>";
echo "<h3>".$row['title']."</h3>";
echo "<p class='description'>".$row['description']."</p>";
echo "</div>";
echo "<img src='images/uploads/".$row['image']."'/>";
// name for submit button, the $row['image'] contains the entire image name so certain characters have to be removed
**$name = str_replace(array(".", "-", ":", "'", "/", " "), "", $row['image']);**
// comment box - just a form with a submit
echo "<div class='commentBox'>
<form action='test.php' method='POST'>
<textarea placeholder='Say something nice!' name='comment'></textarea>
// CREATES NAME FOR BUTTON. FOR EACH IMAGE, THE BUTTON HAS THE IMG NAME
**<button type='submit' name='".$name."' value='submit'> post </button>**
</form>
</div>";
echo "</div>";
}
if(isset($_POST["'".$name."'"]))
{
echo '<script type="text/javascript"> alert("isset"); </script>';
}
When I put the name as a plain string in the $_POST parameters, it works fine but when I put the variable in, it does not work. The $name variable is a string.
This works but I'm sure any string used will work as long as the button name and string in $_POST are the same.
echo "<button type='submit' name='flowerspng' value='submit'> post </button>";
if(isset($_POST[flowerspng]))
{
echo '<script type="text/javascript"> alert("isset"); </script>';
}
This code on the other hand, does not. I know variables can be passed inside $_POST parameters, so I don't understand what's wrong with my code. Is my syntax incorrect? Clearly the variable is not being set otherwise the alert box would pop up.
echo "<button type='submit' name='".$name."' value='submit'> post </button>";
if(isset($_POST["'".$name."'"]))
{
echo '<script type="text/javascript"> alert("isset"); </script>';
}
I have tried this too but I don't think it worked because there are no quotes around $name.
echo "<button type='submit' name=$name value='submit'> post </button>"
if(isset($_POST[$name]))
{
echo '<script type="text/javascript"> alert("isset"); </script>';
}

Answer 1

This code works:
echo "<button type='submit' name='$name' value='submit'> post </button>"
if(isset($_POST[$name]))
{
echo '<script type="text/javascript"> alert("isset"); </script>';
}
I moved the if statement for the isset() function into the end of the while loop, it works for all images now.
while($row = mysqli_fetch_array($result))
{
echo "<div class='wrapper' name=".$row['image'].">";
echo "<div class='caption'>";
echo "<h3>".$row['title']."</h3>";
echo "<p class='description'>".$row['description']."</p>";
echo "</div>";
echo "<img src='images/uploads/".$row['image']."'/>";
$name = str_replace(array(".", "-", ":", "'", "/", " "), "", $row['image']);
echo "<div class='commentBox'>
<form action='test.php' style='text-align: right; background-color: rgb(34,34,34); width: 100%; height: 120%; margin: 0;' method='POST'>
<textarea style='height: 90%; width: 79%; resize: none; border-radius: 3px; margin: 0; margin-top: 5px;' placeholder='Say something nice!' name='comment'></textarea>
<button type='submit' name='$name' value='submit' style='height: 100%; width: 20%; float: right;'> post </button>
</form>
<div class='seeMore'> see more </div>
</div>";
echo "</br><div class='comments' style='display: none;'> comment display </div>";
echo "</div>";
**
// testing the if statement for each image - works perfectly now
if(isset($_POST[$name]))
{
echo '<script type="text/javascript"> alert("'.$name.'"); </script>';
mysqli_query($conn, "UPDATE uploads SET title='test' WHERE image='".$row['image']."'");
header("Refresh:0");
}
**
}