Add a class to next previous pagination

/* ----------------------------------------------------------------------------
   add next page and previewous page classes. Useful for preloading plugins
*/
add_filter('next_posts_link_attributes', 'td_next_posts_link_attributes');
function td_next_posts_link_attributes() {
return 'class="td-next-posts-link"';
}

add_filter('previous_posts_link_attributes', 'td_previous_posts_link_attributes');
function td_previous_posts_link_attributes() {
return 'class="td-prev-posts-link"';
}