Use case: Some websites provide a toc by default, and each time visit these websites, you will see a left-sidebar toc provided by the website itself, and a right-sidebar toc provided by smart-toc. So, it's better to have a toc detection algorithm to hide smart toc itself and sets the default value for new websites that doesn't existing in the setttings. The algorithm can be done by: generating the toc from the website, and then finds if the html source contains the similar tree structure of similar keywords, it true, the smart-toc should hide itself.