Thanks Jarvis, I appreciate that you took the time to reply in detail. This is very interesting. I think I could learn a lot studying your code. Yesterday I moved on to trying a plugin (Search & Filter Pro) which also uses Ajax. I’m having some issues with it (it works fine on my local site but so far no luck on the live) so I may be back to trying to do it on my own if I can’t find a resolution. For now I’ll leave this open just in case…
I just reread my post and don’t see a way to edit it, so a quick clarification:
When I said “I’ve tried using the code in the tutorial, and the code attached below (they are different).” I was referring to the code in the tutorial video and in the snippets attached below that; both from the page I linked to in my post.