how to set first page pagination link to active by default - php

Question

This code only shows one of the pagination links as active if I click on it first. But on page load I want number "1" to be active by default.
if(!empty($_GET['page'])) {
$page = $_GET['page'];
} else {
$page = 1;
}
for ($page = 1; $page <= $number_of_pages; $page++) {
if ($_GET['page'] == $page) {
echo "<li class='pagination__page--active'><span>{$page}</span></li>";
}
else {
echo "<li><a href='product-category/$page_url/page/{$page}'>{$page}</a></li>";
}
}

Answer 1

Is your problem, that only on page 1 it doesn't show the correct one as active?
If so, your problem is that you are probably not sending a 'page' with your GET request. The easiest way to solve this is:
$curr_page = (isset($_GET['page'])) ? $_GET['page'] : 1;
for ($page = 1; $page <= $number_of_pages; $page++) {
if ($curr_page == $page) {
echo "<li class='pagination__page--active'><span>{$page}</span></li>";
}
else {
echo "<li><a href='product-category/$page_url/page/{$page}'>{$page}</a></li>";
}
}