News feed, how to display it in Mozilla extension?

Question

JavaScript

There is `rss`a feed and there is a news block on the page. The task is to make a simple extension that `RSS`would take data from and display news and dates as a headline. I learned how to make a parser using `PHP`it, but how to do it for an extension does not fit in my head. There was an idea to create a separate `html`page on the site and duplicate this news block into it, after closing the indexing in the robots to avoid duplicates, and then `popup.html`place the `iframe`pages in the file. But I don't think this is the best idea. Maybe someone has an idea or links to an example to somehow represent this process. Everything is complicated by the fact that with the help of `js`without `php`you can not parse the block. If I'm wrong write about it. Thanks

Answer 1

Based on correspondence in the comments:
If you don’t know how extensions work in firelis, then read the official manuals or see examples ( by the way, this almost describes your case, you just have to remove the extra functionality and add the output of your data). Getting an RSS feed is very similar to getting any other feed, so there shouldn't be any problems.
"And it is not clear whether php is used there or is it js" - good evening) Extension is a browser extension, it is implemented entirely on web technologies, that is, js + css + html.