No single script error fix can eliminate these errors, and your ability to fix the actual problem are limited if it's not your website. You can verify that the problem is not on your end by trying the same website in a different web browser to see if you get the same or a similar message. You can also try accessing the site from a different computer entirely or on your smart phone if you have one. If you're running browser extensions, you can disable or remove them to see if that makes a difference.
If the Error Recurs
If you've tried the website on multiple computers or browsers and it's still not working properly, it's likely there's a legitimate problem with the site. If you know the people who built the website or they have a contact email address or phone number, you can contact them and report it. Try to provide as much information as possible about what you were doing when you saw the error.