The iframe in HTML stands for Inline Frame. The <iframe> tag defines a rectangular area within the current document or web page. The web browser can display another document within the current page, including the scrollbars and borders. Like every other tag, the <iframe> tag also has a few attributes associated with it.

One of the solution. Below is my work around for this problem: Upload the content to AWS S3, and it will create a https link for the resource. Notice: set the permission to the html file for allowing everyone view it. After that, we can using it as the src of iframe in the https websites.