Loops through each a tag in the `#navbar` and compares it to the url. If it's a match BOOM add active to it.

jarascrit.js

$(document).ready(function() {
  p = location.pathname.replace('/', '').split('/')[0];
    $("#navbar a").each(function() {
      if ( $(this).attr('href').replace('/', '') == p ) {
          $(this).parent().addClass('active');
          return;
      }
  });
});