phpjs/_octopress/source/_includes/custom/navigation.html

php.js offers community built php functions in javascript

<ul class="main-navigation">
  <li><a href="{{ root_url }}/about">About</a></li>
  <li><a href="{{ root_url }}/blog/archives">Blog</a></li>
  <li><a href="{{ root_url }}/functions">Functions</a></li>
  <li><a href="{{ root_url }}/authors">Authors</a></li>
</ul>