Hi Mohan,
You can use the html/javascript snippet widget.
https://appstore.home.mendix.com/link/app/56/Mendix/HTML/-JavaScript-Snippet
Thank you.
I copied all the custom js files to theme/js folder and html files to theme/html and css files to theme/styles/css. I am using the widget as below
But its not showing my custom elements. Am I doing anything wrong?