WordPress: Add Class to first Paragraph in WordPress the_content; (add this to the functions.php in your Theme)

first-paragraph-class.php

<?php
/* =BEGIN: Add Class to first Paragraph in WordPress the_content();
    Source: http://webdevbits.com/wordpress/add-class-to-first-paragraph-in-wordpress-the_content/
   ---------------------------------------------------------------------------------------------------- */
function first_paragraph($content){
  // Testing to see if the content is a Page or Custom Post Type of school, if so, display the text normally (without the class = intro).
  if ( is_page() || ('school' == get_post_type() ) ) {
    return preg_replace('/<p([^>]+)?>/', '<p$1>', $content, 1);
  } else {
    return preg_replace('/<p([^>]+)?>/', '<p$1 class="intro">', $content, 1);
  }
}
add_filter('the_content', 'first_paragraph');
?>