php - I want to use AJAX to make a second-level linkage. I would like to ask the experts if there are any mistakes in my code.

Question

ajax:code][2]

html code:

Controller code:< /span>

Page effect:

Answer 1

Assign variables in the screenshot. I don’t know how think PHP handles it. Let’s write it like this

var _url = "<?=U:(Form.form)?>"

Answer 2

U:(form/form) 要用 <?php ?> Wrap it up.
You can use F12 to see the ajax request details