Mark the current navigation link in PHP

Let the template mark the current page

For a PHP-rendered site, the server can send the active navigation state with the first HTML response. Keep the links in a small array and compare their paths. Parsing a block of HTML line by line, or comparing only its first five characters, can mark the wrong link.

A complete navigation example

<?php
function navPath(string $path): string {
    return rtrim($path, '/') ?: '/';
}
function navEscape(string $value): string {
    return htmlspecialchars($value, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
}

$requestPath = parse_url($_SERVER['REQUEST_URI'] ?? '/', PHP_URL_PATH);
$current = is_string($requestPath) ? navPath($requestPath) : null;
$links = [
    ['href' => '/', 'label' => 'Home'],
    ['href' => '/about/', 'label' => 'About'],
    ['href' => '/work/', 'label' => 'Work'],
    ['href' => '/contact/', 'label' => 'Contact'],
];
?>
<nav aria-label="Main">
  <ul>
    <?php foreach ($links as $link):
        $active = $current === navPath($link['href']);
    ?>
      <li>
        <a href="<?= navEscape($link['href']) ?>"<?= $active ? ' class="is-active" aria-current="page"' : '' ?>>
          <?= navEscape($link['label']) ?>
        </a>
      </li>
    <?php endforeach; ?>
  </ul>
</nav>

Put the functions in a shared helper loaded once if several templates use them. The example link list is trusted application configuration; escaping an arbitrary URL does not make an unsafe URL scheme safe.

Matching rules

/work, /work/ and /work/?utm_source=newsletter match the Work link. /workshop/ does not. This ignores the query string deliberately; an application whose pages are selected by query parameters should use its router's resolved route instead.

For a section highlight on /work/example/, add an explicit slash-boundary descendant check. Keep the Home link exact, or every page will match it. Do not decode arbitrary request paths differently from your router.

Style .is-active or [aria-current="page"] in the existing navigation stylesheet. Include a visible cue such as weight or an underline and preserve keyboard focus styles. No JavaScript is needed for this version.

References: PHP parse_url, HTML escaping, and aria-current.

<?php
$nav = <<<NAV
<ul>
  <li><a href="/">Home</a></li>
  <li><a href="/about">About Us</a></li>
  <li><a href="/work">Work</a></li>
  <li><a href="/blog">Blog</a></li>
  <li><a href="/contact">Contact</a></li>
</ul>
NAV;

$lines = explode("\n", $nav);
foreach ($lines as $line) {
    $current = false;
    preg_match('/href="([^"]+)"/', $line, $url);
    if (substr($_SERVER["REQUEST_URI"], 0, 5) == substr(@$url[1], 0, 5)) {
        $line = str_replace('<a h', '<a  class="active" h', $line);
        }
    echo $line."\n";
}
?>