How to track an error in loading a script on a website?

Question

JavaScript

Good afternoon!
The error is repeated on several sites based on CMS Opencat. After clicking on the buy button, the page hangs and the button becomes unavailable. How can I trace the cause of the freeze? Are there any services? Ways?

Answer 1

Ways?

Straight arms + console + debugger

Answer 2

In Chrome , Ctrl+Shift+I tabs Console , Network and forward.