The CRUD generator of Gii has done a wonderful job for you, and you already have a list of items in the "index" page and a detailed view of a specified item in the "view" page.
Yii Framework Wiki
Wiki articles in category How-tos tagged with "AJAX"
Showing 1-2 of 2 items.
Render Form in popup via AJAX (Create and Update) with ajax validation & Also load any page via ajax Yii 2.0 (2.3)
There are a few issues with the other solutions I originally used that I found from other wikis. I address the issues I had in this much simpler and shorter way. I am also going to explain what is going into way more detail than others to help people understand what's going on.