Problem with displaying correct hidden field - php

Question

This is my HTML:
<form method="POST" action="">
<?php
$skillSubCategory = $skills->showSkills(24);
for ($i = 0; $i < count($skillSubCategory); $i++) {
?>
<input type="hidden" name="skillid" value="<?php echo $skillSubCategory[$i]['skill_id']; ?>" />
<?php echo $skillSubCategory[$i]['title']; ?>
<input type="submit" name="add" value="add" /><br />
<?php } ?>
</form>
<?php if (isset($_POST['add'])) {
echo $_POST['skillid'];
} ?>
Resulting source code:
<form method="POST" action="">
<input type="hidden" name="skillid" value="25" />
Animal Grooming
25
<input type="submit" name="add" value="add" /><br />
<input type="hidden" name="skillid" value="26" />
Dog Trainer
26
<input type="submit" name="add" value="add" /><br />
<input type="hidden" name="skillid" value="27" />
Dog Walking
27
<input type="submit" name="add" value="add" /><br />
<input type="hidden" name="skillid" value="28" />
Vet
28
<input type="submit" name="add" value="add" /><br />
<input type="hidden" name="skillid" value="29" />
Beekeeping
29
<input type="submit" name="add" value="add" /><br />
</form>
What it looks like:
I get number 29 for any button clicked. Any ideas what's wrong? Why the correct number wont show up when i click add?

Answer 1

You can also use the buttons themselves(without changing their values):
<input type="submit" name="skillid[25]" value="add" />
<input type="submit" name="skillid[26]" value="add" />
<input type="submit" name="skillid[27]" value="add" />
To retrieve the submitted value(its not the value in this case, its the first key of the posted array):
if(isset($_POST['skillid']) && is_array($_POST['skillid']))
{
echo key($_POST['skillid'])
}

Answer 2

Because when you have multiple fields with the same name attribute in a form, the last one always takes precedence (with the exception of submit buttons -- the one clicked will be the only one considered). So the last hidden input with the name skillid will always be sent to the server.
When using forms like this, you usually have to use separate forms for each button. Alternatively, change the value attribute of each button and consider that from your PHP code.

Answer 3

Change:
<form method="POST" action="">
to:
<form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
then change the condition to:
if (isset($_POST['add']) && isset($_POST['skillid'])) {
EDIT: use the <option> tag instead
<select name="skillid">
<option value="25">Animal Grooming</option>
<option value="26">Dog Trainer</option>
...
</select>
Your PHP code now will be:
<form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<?php
$skillSubCategory = $skills->showSkills(24);
<select name="skillid">
for ($i = 0; $i < count($skillSubCategory); $i++) { ?>
<option value="<?php echo $skillSubCategory[$i]['skill_id']; ?>"><?php echo $skillSubCategory[$i]['title']; ?></option>
<?php } ?>
</select>
<input type="submit" name="add" value="add" /><br />
</form>
if (isset($_POST['add']) && isset($_POST['skillid'])) {
echo $_POST['skillid'];
} ?>