navbar-version-selector.html

{{ if .Site.Params.versions -}}
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-bs-toggle="dropdown" aria-expanded="false">
   {{ .Site.Params.version_menu }}
</a>
<div class="dropdown-menu" id="version-dropdown-menu" aria-labelledby="navbarDropdown">
   <div w3-include-html="{{ .Site.Params.releases_url }}" w3-include-html-default='<a class="dropdown-item" href="{{ .Site.Params.global_logo_url }}dev/">Dev</a>'></div>

   <script>
      w3.includeHTML(function() {
      const basePath = "{{ site.BaseURL | relURL }}";

      function stripBase(path) {
          if (path.startsWith(basePath)) return path.substring(basePath.length);
          if (basePath === "/" && path.startsWith("/")) return path.substring(1);
          return path.replace(/^\//, '');
      }

      document.getElementById('version-dropdown-menu').addEventListener('click', function(e) {
        const link = e.target.closest('a.dropdown-item');
        if (!link) return;
        e.preventDefault();

        let targetPath = link.pathname;
        if (!targetPath.endsWith('/')) targetPath += '/';

        let cleanCurrentPath = stripBase(window.location.pathname);
        const allLinks = document.querySelectorAll('#version-dropdown-menu a.dropdown-item');
        let currentVersionPrefix = "";

        allLinks.forEach(a => {
            let cleanVPath = stripBase(a.pathname);
            if (!cleanVPath.endsWith('/')) cleanVPath += '/';
            if (cleanVPath !== "" && cleanVPath !== "/" && cleanCurrentPath.startsWith(cleanVPath)) {
                if (cleanVPath.length > currentVersionPrefix.length) {
                    currentVersionPrefix = cleanVPath;
                }
            }
        });

        let deepPath = cleanCurrentPath;
        if (currentVersionPrefix !== "") {
            deepPath = cleanCurrentPath.substring(currentVersionPrefix.length);
        }
        deepPath = deepPath.replace(/^\//, '');

        const fullTargetPath = targetPath + deepPath;

        // Perform a HEAD request to check if the deep route exists
        fetch(fullTargetPath, { method: 'HEAD' })
          .then(response => {
            if (response.ok) {
              // Page exists! Redirect to deep path
              window.location.href = fullTargetPath;
            } else {
              // 404 or other error: Fallback to the version root
              window.location.href = targetPath;
            }
          })
          .catch(() => {
            // If the fetch fails entirely, fallback to root
            window.location.href = targetPath;
          });
      });
    });
   </script>
</div>
{{ end -}}