Question

Please not not turn this into a discussion about which browser is better and the ethics of forcing a browser. It’s an intranet, and it’s what I am required to do so everyone calm down =o)

I need to prevent employees from trying to bypass the check to not use their preferred browser instead of the company mandated one + version. The decision was made based on security, compatibility, costs, and the use of company made Firefox extensions.

I came across this Force users to use Chrome/FireFox instead of IE which I can do easily in PHP to force use of Firefox, however it relies on the useragent which can easily be changed in numerous browsers and with the use of plugins.

Is there a JavaScript solution that I can use that DOES NOT check the useragent or any value that can be ‘easily’ modified by a user/plugin? It would need to detect if the browser is Firefox and what version it is. Site uses jQuery so if it can be done using that, however not required then by all means yes. I just am not aware of what ways to detect a browser and it’s version that there are without checking useragent.

I remember way back in the day for detecting Netscape or some browser checking for document.all was used instead of useragent, so I’m guessing something similar, which only Firefox will have.

Thank you very much in advance!

Answer 1

Try this: http://jsfiddle.net/DerekL/62exH/

Because Firefox handles onpopstate differently than other browsers, you can then use this to detect if it is Firefox or not. This can not be changed by user or script. But the disadvantage is you can only get the version number by doing navigator.appVersion.