Use mozilla's 4 week release schedule and the approximate date of the current Firefox release to determine the likely latest Firefox release. Microsoft could block or otherwise render useless the script based on the useragent that's hardcoded with a firefox release from 2 years ago.
Use mozilla's 4 week release schedule and the approximate date of the current Firefox release to determine the likely latest Firefox release. Microsoft could block or otherwise render useless the script based on the useragent that's hardcoded with a firefox release from 2 years ago.