Codeigniter + Infinity scroll help

So this is two part problem really, one is making Ajax call with JavaScript on your page in browser when certain conditions are met, either dropdown change or user scrolls to the end (or my personally preferred option with "Show more" button).

And second part is making a controller that returns correct data.

How are you doing your front end? Vanilla or jQuery JS, or are you using a full front-end framework?

Well let's say that i make the first part as for the Ajax. Have you ever created something like that? Or is there any examples where i can start from? 

As for the second part, so you mean that this is possible to be created with a single controller right? 

I use Jquery. I've created a dynamic dependend dropdown but this approach:

Code:

$output = '';
$output .= '<div>';
$output .= '<span>';
$output .= 'etc... etc..';
$output .= '</span>';
$output .= '</div>';

it's kinda messed up since it's not just a single dropdown option, but some divs inside other divs etc.. etc.. 

So any ideas on that?

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