Pass user_id in a table to another page - php

Question

I have a list of users that I'm reporting in a table. The first column contains the user_id, and I want to pass that to another page that displays the users details. I don't want to pass it through the URL with $_GET. How do I do this? I can use only HTML & PHP. One post I saw seemed like it was on the right track, but I can't get it to work. Here's what I have:
<h1>Maintain Users</h1>
<div id="ir-report">
<table class="table">
<tr class = "table tr">
<th class="table th">User Id</th>
<th>Username</th>
<th>Name</th>
<th>Email</th>
<th>Activated?</th>
<th>Type</th>
<th>Account Nbr</th>
</tr>
<?php while ($row = mysqli_fetch_assoc($query))
{?>
<tr class="table tr">
<td class ="table td" onclick="submit_id($row['user_id'])"><img src="images\editpensil.jpg" alt="UserId" width="25" height="25"></td>
<td><?php echo $row['username'] ?></td>
<td><?php echo $row['first_name'] ?></td>
<td><?php echo $row['email'] ?></td>
<td><?php echo $row['active'] ?></td>
<td><?php echo $row['type'] ?></td>
<td><?php echo $row['acct_nbr'] ?></td>
</tr>
<?php } ?>
</table>
</div>
What I was expecting to happen is that "on click" the function submit_id($var) would be called. To test that this is working, my function is very simple for the moment:
function submit_id($var) {
header('Location: index.php');
exit();
}
But nothing happens when I clime on the edit icon (editpensil.jpg). The application doesn't appear to try and execute anything. What am I missing? -- Thanks.

Answer 1

You can't call a PHP function from an onclick attribute, or any other on attribute. Those functions must be Javascript functions.
If you really need/want to not pass the id through GET, you can wrap the table in a <form> with the action set to the page you want to send it to, with a method of POST and a hidden input field. I know your question says you can only use HTML and PHP; without Javascript, the only way you can really do this is to add a button to the form/table. You could use CSS to style it so it looks like a link, or anything not-button like.
Example without Javascript:
<form action="index.php" method="post">
<tr class="table tr">
<td class ="table td">
<img src="images\editpensil.jpg" alt="UserId" width="25" height="25">
</td>
<td><?php echo $row['username'] ?></td>
<td><?php echo $row['first_name'] ?></td>
<td><?php echo $row['email'] ?></td>
<td><?php echo $row['active'] ?></td>
<td><?php echo $row['type'] ?></td>
<td><?php echo $row['acct_nbr'] ?></td>
<td><input type="submit" value="Link to" /></td>
</tr>
<input type="hidden" name="user_id" value="<?php echo $row['user_id'] ?>" />
</form>
When that button is clicked, the form will be posted to index.php and you can get to the id through $_POST['user_id']
If you are willing and able to use Javascript, you should be able to do the following HTML/PHP:
<form action="index.php" method="post" id="user_form_<?php echo $row['user_id'] ?>">
<tr class="table tr">
<td class ="table td user_id_link" data-userid="<?php echo $row['user_id'] ?>">
<img src="images\editpensil.jpg" alt="UserId" width="25" height="25">
</td>
<td><?php echo $row['username'] ?></td>
<td><?php echo $row['first_name'] ?></td>
<td><?php echo $row['email'] ?></td>
<td><?php echo $row['active'] ?></td>
<td><?php echo $row['type'] ?></td>
<td><?php echo $row['acct_nbr'] ?></td>
</tr>
<input type="hidden" name="user_id" value="<?php echo $row['user_id'] ?>" />
</form>
And the following Javascript, although this will only work in IE9+:
var links = document.getElementsByClassName('user_id_link');
for (link in links) {
link.addEventListener('click', function() {
var formId = 'user_form_' + this.userid;
document.getElementById(formId).submit();
}, false);
}
Or the much cleaner jQuery version, which has better browser compatibility and is really an invaluable toolkit for a web developer:
HTML/PHP:
<form action="index.php" method="post">
<tr class="table tr">
<td class ="table td user-id-link">
<img src="images\editpensil.jpg" alt="UserId" width="25" height="25">
</td>
<td><?php echo $row['username'] ?></td>
<td><?php echo $row['first_name'] ?></td>
<td><?php echo $row['email'] ?></td>
<td><?php echo $row['active'] ?></td>
<td><?php echo $row['type'] ?></td>
<td><?php echo $row['acct_nbr'] ?></td>
</tr>
<input type="hidden" name="user_id" value="<?php echo $row['user_id'] ?>" />
</form>
Javascript/jQuery:
$(function() {
$('.user-id-link').on('click', function() {
$(this).closest('form').submit();
});
});

Answer 2

You're mixing PHP and JS. The function called in an onclick handler must be JS, it cannot be php.
What's wrong with passing the id through the URL? That's quite obviously the only simple practical solution. Alternatives are:
using cookies, but that's a mess if a user opens multiple tabs/windows on your site, or wants to bookmark the page, or for a reopen after restart of the browser. And that really doesn't help much.
using some kind of other id that points to the user id, but that's just adding another layer for not much.
Unless you tell us exactly why you don't want to pass the id through the URL, it will be difficult to suggest anything.