Originally posted by Adamthenewbie
thats sweet. thanks. I just assumed since PHP was a server side language it couldnt tell me anything about the client
The User Agent string is sent by the client as part of each request it makes to the server - the idea being of course that it then allows client-type-specific content to be generated.
It's not 100% reliable, since you're trusting the client not to lie about what it is. It's probably more like 99.5%, and clients who do lie do so with the expectation that there might be problems.