Thanks a lot. This is very close to what I am looking for, and saves a lot of my time. I am grateful to all the help I received from this mailing list.

It is a lot of fun subscribing to this list.

Regards

Ziping

> On Jan 21, 2022, at 11:46 AM, Max Nikulin <manikulin_at_gmail_com_fcq2724cv3y0tc_re5x9491@icloud.com <mailto:manikulin_at_gmail_com_fcq2724cv3y0tc_re5x9491@icloud.com>> wrote:
> 
> On 21/01/2022 19:23, Juan Manuel Macías wrote:
>> ZIPING CHEN writes:
>>> I may have many things like this in the middle of the file.
>>> ************************** a new heading.
>>> 
>>> I wish to turn all layers of
>>> headings in org file into collapsable headline to html.
>>> 
>>> Does anybody know a way I can accomplish this?
>> I think that you need to add javascript and enclose the collapsible
>> content in a div. 
> 
> Have a look at info "(org) JavaScript support" https://orgmode.org/manual/JavaScript-support.html <https://orgmode.org/manual/JavaScript-support.html> (I have not tried that folding view).
> 
> HTML has <details><summary>header</summary>body</details> elements that works without JS, but it will require custom exporter.
> 
> You should ensure that deep headings can not be recognized as org inline tasks. Check ox-html, it may has limit on number of levels that are exported as headings with switching to lists for deeper structures.
> 
>