//文章目录
function article_index($content) {
  $matches = array();
  $ul_li = '';
  $r = '/<h([2-6]).*?\>(.*?)<\/h[2-6]>/is';
  if(preg_match_all($r, $content, $matches)) {
    foreach($matches[1] as $key => $value) {
      $title = trim(strip_tags($matches[2][$key]));
      $content = str_replace($matches[0][$key], '<h' . $value . ' id="title-' . $key . '">'.$title.'</h'. $value .'>', $content);
      $ul_li .= '<li><a href="#title-'.$key.'" title="'.$title.'">'.$title."</a></li>\n";
    }
    $content = "\n<div id=\"article-index\">
    <strong>文章目录</strong>
    <ul id=\"index-ul\">\n" . $ul_li . "</ul>
    </div>\n" . $content;
  }
  return $content;
}

模板调用代码
<?php echo article_index($navinfor[newstext]);?>

CSS样式
/*正文标题索引*/
#article-index {
  border-radius: 6px 6px 6px 6px;
  border: 1px solid #DEDFE1;
  
  margin: 0 0 15px 0;
  padding: 0 6px;
 
  line-height: 23px;
}
#article-index strong {
  border-bottom: 1px dashed #DDDDDD;
  display: block;
  line-height: 30px;
  padding: 0 4px;
  color: #DE0208;
}
#index-ul {
  margin: 8px 0px 0px 0px;
  padding-bottom: 10px;
  padding-left: 0px;
}
#index-ul li {
  background: none repeat scroll 0 0 transparent;
  list-style-type: disc;
  padding: 0;
  margin-left: 20px;
}