Extracts and returns table of contents (toc) and bookmarked content from any html.

get_toc.php

<?php
 
function create_toc( $content ) {
	preg_match_all( '/<h([1-6])(.*)>([^<]+)<\/h[1-6]>/i', $content, $matches, PREG_SET_ORDER );
 
	global $anchors;
 
	$anchors = array();
	$toc 	 = '<ol class="toc">'."\n";
	$i 		 = 0;
 
	foreach ( $matches as $heading ) {
 
		if ($i == 0)
			$startlvl = $heading[1];
		$lvl 		= $heading[1];
 
		$ret = preg_match( '/id=[\'|"](.*)?[\'|"]/i', stripslashes($heading[2]), $anchor );
		if ( $ret && $anchor[1] != '' ) {
			$anchor = stripslashes( $anchor[1] );
			$add_id = false;
		} else {
			$anchor = preg_replace( '/\s+/', '-', preg_replace('/[^a-z\s]/', '', strtolower( $heading[3] ) ) );
			$add_id = true;
		}
 
		if ( !in_array( $anchor, $anchors ) ) {
			$anchors[] = $anchor;
		} else {
			$orig_anchor = $anchor;
			$i = 2;
			while ( in_array( $anchor, $anchors ) ) {
				$anchor = $orig_anchor.'-'.$i;
				$i++;
			}
			$anchors[] = $anchor;
		}
 
		if ( $add_id ) {
			$content = substr_replace( $content, '<h'.$lvl.' id="'.$anchor.'"'.$heading[2].'>'.$heading[3].'</h'.$lvl.'>', strpos( $content, $heading[0] ), strlen( $heading[0] ) );
		}
 
		$ret = preg_match( '/title=[\'|"](.*)?[\'|"]/i', stripslashes( $heading[2] ), $title );
		if ( $ret && $title[1] != '' )
			$title = stripslashes( $title[1] );
		else	
			$title = $heading[3];
		$title 		= trim( strip_tags( $title ) );
 
		if ($i > 0) {
			if ($prevlvl < $lvl) {
				$toc .= "\n"."<ol>"."\n";
			} else if ($prevlvl > $lvl) {
				$toc .= '</li>'."\n";
				while ($prevlvl > $lvl) {
					$toc .= "</ol>"."\n".'</li>'."\n";
					$prevlvl--;
				}
			} else {
				$toc .= '</li>'."\n";
			}
		}
 
		$j = 0;
		$toc .= '<li><a href="#'.$anchor.'">'.$title.'</a>';
		$prevlvl = $lvl;
 
		$i++;
	}
 
	unset( $anchors );
 
	while ( $lvl > $startlvl ) {
		$toc .= "\n</ol>";
		$lvl--;
	}
 
	$toc .= '</li>'."\n";
	$toc .= '</ol>'."\n";
 
	return array( 
		'toc' => $toc,
		'content' => $content
	);
}