Sometimes, html caching will occur when we use dynamic php pages to call html, so you can add the following code to the html header, and the html will not be cached.
<meta HTTP-EQUIV="pragma" CONTENT="no-cache"><meta HTTP-EQUIV="Cache-Control" CONTENT="no-cache, must-revalidate"><meta HTTP-EQUIV="expires" CONTENT="0">
In the php page, you can add:
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");header("Cache-Control: no-cache, must-revalidate");header("Pragma: no-cache");