If it's your website, then you have a secret error somewhere in your secret code. You need to fix that.
If it's someone else's website, then they need to fix it. You should report it to them, assuming you can find a way to contact them with their website so fundamentally broken.
Either way, there's nothing we can do to help you. We don't have access to the affected code. Fortunately, all major browsers have the tools that you, or the site authors, need to do the job:
JavaScript Debugging[
^]