How to add a class and title attribute to the link generated by next/previous post

Question

The following code

<?php previous_post('%', '&#60;', 'no'); ?>
<?php next_post('%', '&#62; ', 'no'); ?>

returns these links, as it should

<a href="post_address/"><</a>
<a href="post_address/">></a>

My question is about adding a class and title attribute so that the code returns

<a class="normalTip" title="Previous Project" href="post_address/"><</a>
<a class="normalTip" title="Next Project" href="post_address/">></a>

I am using the iWR Tooltip plugin and would like to use it on the links for the post navigation.

There is probably a simple solution by adding something to the function.php file, but I have not come up with the answer. Any ideas?

Answer 1

previous_post and next_post are deprecated. you should be using previous_post_link and next_post_link. That function applies the {$adjacent}_post_link filter. You can use that to get what you want. A very, very crude example:

function construct_np_attr_wpse_92086($matches) {
  if ('prev' == $matches[1]) {
    $np = 'Previous';
  } else {
    $np = 'Next';
  }
  $ret = 'rel="'.$matches[1].'" class="normalTip" ';
  if (!empty($np)) {
    $ret .= 'title="'.$np.' Project"';
  }
  return $ret;
}
function add_attr_to_np_links_wpse_92086($link) {
  return preg_replace_callback('/rel="([^"]+)"/','construct_np_attr_wpse_92086',$link);
}
add_filter('next_post_link','add_attr_to_np_links_wpse_92086');
add_filter('previous_post_link','add_attr_to_np_links_wpse_92086');

Answer 2

jQuery makes it pretty easy to add a class to an element in the DOM. The code looks like this:

$("p").addClass("myClass yourClass");

Pretty simple, eh? You can see more of the jQuery documentation here: http://api.jquery.com/addClass/