This is probably something the webmaster of the affected site can help you with. There are many causes as to why this can happen but most often is caused by the website calling for something which causes the crash.

Clearing your cache and cookies for the site might help also.

Please let us know if this simple thing works or if you need further help

Is this something that Firefox displays or do you see this on the web page?

It is possible that the website doesn't support your preferred language as set in Options. You can try to set 'en' or 'en-US' as the first language choice if this is currently another language.

• Options/Preferences -> Content -> Languages