Sometimes you have the necessity to put in a fixed position of every article of your site a block of content, in my case one or more adverts, but Drupal 8 and its new theming system doesn't help you much. So I'll try to show you my first rough solution via jQuery and iframe, hoping to obtain some idea to improve it or another method more efficient, maybe through only Twig.
I have tried to adapt my old Python application written for S60 smartphones into a modern webapp which should be able to work in any recent internet browser. Therefore I have used jQuery Mobile to convert it and it was very easy, nevertheless my terrible programming skills. Below there is my final app and some description.
Recently I have restarted to program the first web-app: the conversion of my storm sewer software. I focalized my attention on the input interface and despite the easiness and versatility of jQuery, I have got bogged down in details. I have reached a “result” but is full of bugs and not optimal.