Three leve cascading dropdowns in Sharepoint using Jquery

Hi Team and Pramod Bhosale in particular,

I have followed all the instruction provided here: https://www.c-sharpcorner.com/article/three-level-cascading-dropdown-sharepoint-list-by-using-javascript-and-script-ed4/ but the script won't load and it's controlling menus.

I'm working on a intranet.