Submitting Form Replaces Constant GET Information That Is Needed For The Page

I'm learning php and I've got to say I've googled everywhere and I'm stuck :( My question is, in other words, how can I get new variables added to previous variables on the page? I

Solution 1:

Instead of submitting to an action URL with part of the query string already filled out, use a hidden input field to hold the values of the variables you want to be fixed. See if you can get your PHP script to generate a form like this:

<form action="getvartest.php" method="get">
  <input type="hidden" name="orgvar" value="12345" />
  <select name="varselection">
    <option value="selection1">selection1</option>
    <option value="selection2">selection2</option>
  </select>
  <input type="submit" />
</form>

Perhaps something like:

<input type="hidden" name="orgvar" value="<?= htmlspecialchars($_GET['orgvar']) ?>" />

(The htmlspecialchars() call escapes characters like <, &, and " just in case there are any of these in orgvar.)

Or if you wanted to save every query parameter you could use a generic loop like:

<?php foreach ($_GET as $name => $value) { ?>
    <input type="hidden" name="<?= htmlspecialchars($name)  ?>"
                        value="<?= htmlspecialchars($value) ?>" /> 
<?php } ?>