Is textarea always accesible throught textarea#content in wordpress dashboard for a specific page?

Question

In the wordpress dashboard/admin area of a page. I add this event handler to jQjuery. When I click the button with the name btnSave the content-editor replaces it's content to the text wow (It's not my final intention to just replace it with text wow but that does not matter for the question I'm asking).

 $('body').on('click', 'div input[name="btnSave"]', function() {
     $('textarea#content').html('wow');
 });

I'm using the default theme. Is textarea always accesible throught textarea#content in wordpress dashboard for a specific page? (when logged in) (Or does/may it differ between different themes?)

Or is there are more "safe" way of doing this? (100% safe that it will work unregardlessly of theme and wordpress version)

I'm creating a plugin with some settings for a specific page. When I change settings I want those settings to reflect directly in the content-editor (without saving anything).

Answer 1

If someones stumbles on the same question. The short answer is yes.

I've tested around ten totally different themes and I didn't have any issue with any of them. I have only tested when using "Classic editor" (not Guthenberg) so it may differ if you use Guthenburg because it's a another way of retrivering info etc.

I cannot say yes with 100% (because I've "only" tested with 10 different themes) clarity but 99,9% probably :-)