Returns HTML for a breadcrumb trail.
$variables: An associative array containing:
function theme_breadcrumb($variables) {
$breadcrumb = $variables['breadcrumb'];
$output = '';
if (!empty($breadcrumb)) {
$output .= '<nav role="navigation" class="breadcrumb">';
// Provide a navigational heading to give context for breadcrumb links to
// screen-reader users. Make the heading invisible with .element-invisible.
$output .= '<h2 class="element-invisible">' . t('You are here') . '</h2>';
$output .= '<ol><li>' . implode('</li><li>', $breadcrumb) . '</li></ol>';
$output .= '</nav>';
}
return $output;
}