What is the best way for a website to check if a user has installed a client app?
问题 Let's say I've got a website that works better if a client has installed and logged into a desktop application. I'd like to be able to do 2 things: Alter the website if they haven't installed the app (to make it easy for them to find a link to the installer) If they've installed the app on a couple of machines, determine which machine they are browsing from I'd like something that works on Windows and OSX, on any of the major browsers. Linux is a bonus. A few thoughts: Websites can detect if