This should be a problem, because each application creates its own header. My Apache server receives this as a browser: [APPNAME] /1.0_CFNetwork/459_Darwin/10.3.0
You can search for Darwin, but I do not know if it is waterproof.
JS-Snippet should look like this:
if (navigator.userAgent.indexOf("Firefox") != -1) { document.write('You're using Mozilla Firefox'); }
source share