From 7fdc36425d641ee862b7ea3790ef4e697028ce93 Mon Sep 17 00:00:00 2001
From: Eric van der Vlist <vdv@dyomedea.com>
Date: Sat, 9 May 2020 11:58:28 +0200
Subject: [PATCH] Checking if we have headers (#2).

---
 extended-toc.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/extended-toc.php b/extended-toc.php
index eeada82..57501c7 100644
--- a/extended-toc.php
+++ b/extended-toc.php
@@ -433,6 +433,10 @@ if( !class_exists('ExToC') ) {
     private function exctract_headings($pagenum) {
       /** find all header tags within the page **/
       preg_match_all('/(<h([1-6]{1})[^>]*>).*<\/h\2>/msuU', $this->pages[$pagenum-1], $matches, PREG_SET_ORDER);
+      
+      if (count($matches) == 0) {
+          return null;
+      }
 
 			/** Check the headings that are desired */
 			if( count($this->options['heading_levels']) != 6 ) {