Display dynamically added Multi Array elements - php

Question

I have a javascript which creates two types of elements.
The PHP code is added on submiting the form, but I show it above.
The First type looks like this:
<tr class="disc">
<span><?php echo $disc_number ?></span>.
</tr>
The Second type looks like this:
<tr class="track">
<input name="trackNumbers[]" value="<?php echo $track_number ?>" />
<input name="discNumbers[]" value="<?php echo $disc_number ?>" />
</tr>
The "track" elements can be multiple for one "disc" element.
For example:
<tr class="disc">
<span>1</span>.
</tr>
<tr class="track">
<input name="trackNumbers[]" value="1" />
<input name="discNumbers[]" value="1" />
</tr>
<tr class="track">
<input name="trackNumbers[]" value="2" />
<input name="discNumbers[]" value="1" />
</tr>
<tr class="disc">
<span>2</span>.
</tr>
<tr class="track">
<input name="trackNumbers[]" value="1" />
<input name="discNumbers[]" value="2" />
</tr>
<tr class="track">
<input name="trackNumbers[]" value="2" />
<input name="discNumbers[]" value="2" />
</tr>
To show on submit each "track" element I am using "for" command.
for ($track_i = 0; $track_i < $total_tracks; $track_i++)
But what about "disc" elements? How to make my "disc" elements to also display on submit, and to have their "track" elements after them.

Answer 1

If I catch your meaning correctly, you need to associate the track elements with the disc numbers... so use a multi-dimensional array:
<tr class="track">
<input name="trackNumbers[<?php echo $disc_number ?>][]" value="<?php echo $track_number ?>" />
</tr>
If I recall correctly, this will produce (in PHP when submitted) an array of arrays, where each first-level array (one per disc) contains an array of tracks (one per track).
foreach($_POST['trackNumbers'] as $discNumber => $tracksArray) {
...

Answer 2

The way you have it setup now is you have two separate arrays track and disc, to get the track number associated to the proper disc I would set up the input element like so:
<input name="trackNumbers[1][]" value="2">
Where 1 is the disc number, you may want to pass in disc numbers once and then use them on the backend to loop through and pull out all the tracks that correspond to the disc numbers.