Mozilla/5.0 (platform rv:geckoversion) Gecko/geckotrail appname/appversion Mozilla/5.0 (platform rv:geckoversion) Gecko/geckotrail Firefox/firefoxversion appname/appversion

Note: The recommended way of sniffing for Gecko-based browsers (if you have to sniff for the browser engine instead of using feature detection) is by the presence of the ' Gecko' and ' rv:' strings, since some other browsers include a ' like Gecko' token.įor other products based on Gecko, the string can take one of two forms, where the tokens have the same meaning except those noted below: