Forms nesting, more submit buttons in a form - forms

Question

I am aware that you can't nest forms in html. Therefore I need help to make the following feature.
I have a list of checkboxes:
<form action="addAll.php" method="post">
<ul>
<li><input type="checkbox" name="boxes[]" value="1"> No. 1</li>
<li><input type="checkbox" name="boxes[]" value="2"> No. 2</li>
<li><input type="checkbox" name="boxes[]" value="3"> No. 3</li>
<li><input type="checkbox" name="boxes[]" value="4"> No. 4</li>
</ul>
<input type="submit" value="Add all">
</form>
When clicking the submit button "Add all", the values are gathered and sent to the addAll.php file. So far, so good.
There are links in the list, as shown. The wanted feature is now that when I click a link, the form is submitted to ANOTHER page than addAll.php.
So actually, instead of the links I need four submit buttons in place of each link, that each will submit the form to THEIR OWN file and not addAll.php.
I simply need to be able to save, which checkboxes the user has checked when he navigates between the links and back again, until he finally at some point clicks the "Add all" submit button. Therefore I want to bring the checked boxes with the user to the new page after clicking the link, so it is save and so I can re-check the checkboxes by looking at the POST data, if he returns later to click "Add all".
Is there a solution for this?

Answer 1

I would not recommend doing anything like this, but to me it seems to be the closest thing I can think of as a solution w/o using javascript.
addAll.php
...
function redirect($url) {
$query_string = urlencode('?boxes=['.implode(',', $_POST['boxes']).']');
$base_url = some_awkward_way_of_getting_the_base_url();
$url_full = $url_base.$url;
header('Location: '.$url_full.$query_string);
}
function alternative($url) {
$_SESSION['boxes'] = $_POST['boxes'];
$base_url = some_awkward_way_of_getting_the_base_url();
$url_full = $url_base.$url;
header('Location: '.$url_full);
}
if (isset($_POST['submit_nr1']))
redirect('nr1.php');
else if (isset($_POST['submit_nr2']))
redirect('nr2.php');
else if (isset($_POST['submit_nr3']))
redirect('nr3.php');
else if (isset($_POST['submit_nr4']))
redirect('nr4.php');
else if (isset($_POST['submit_all']))
handle_accordingly();
...
Alternatively you could have addAll.php include/require different files based on the different cases instead of doing header redirection.
checkboxes.php
...
<form action="addAll.php" method="post">
<ul>
<li>
<input type="checkbox" name="boxes[]" value="1">
<input type="submit" name="submit_nr1" value="No. 1"/>
</li>
<li>
<input type="checkbox" name="boxes[]" value="2">
<input type="submit" name="submit_nr2" value="No. 2"/>
</li>
<li>
<input type="checkbox" name="boxes[]" value="3">
<input type="submit" name="submit_nr3" value="No. 3"/>
</li>
<li>
<input type="checkbox" name="boxes[]" value="4">
<input type="submit" name="submit_nr4" value="No. 4"/>
</li>
</ul>
<input type="submit" name="submit_all" value="Add all">
</form>
...
Disclaimer: I haven't written PHP in a good while, and this is untested, but should at least illustrate a possible solution.