为什么这个AJAX请求在JSFiddle中不起作用 - 虽然它在我的网站上运行良好？

I've been trying to debug something for over 8 hours, and in order to get a proper example to ask the question of why it's not working, I'm trying to put together a JSFiddle replica, but the AJAX request doesn't seem to make the call. Any help in finding out why would be greatly appreciated!I've been trying to debug something for over 8