Don't open any of those JavaScript files. If they are the ones distributed over the past year, they install a Registry-based malware infection that is difficult to remove, although Malwarebytes Anti-Malware might be able to do it. See: [[Troubleshoot Firefox issues caused by malware]]. Unfortunately, it is trivial to steal the Firefox logo and throw up a fake web page to convince users to download a file. Phishing is all around us, not limited to fake banking sites. Redirects to that page have been traced to ad networks on popular sites. To defend yourself, if you aren't already using an ad blocking extension, you might consider trying one out. For example: https://addons.mozilla.org/firefox/addon/ublock-origin/ See also: [[I found a fake Firefox update]]