Adding CatchJS to your site is dead simple.
The first step is to sign up to a plan. Choose the plan that fits your expected usage pattern. You can change this at any time.
Once you have an account and you're logged in, go to the account settings page. Click your name in the top right, and then on "Account settings".
Enter the domain you want to associate with your account.
Add the following HTML to your site to start logging errors.
That's it! Once errors occur in your users' browsers, they will show up in your "errors" tab.