Detecting the user’s browser type and version is helpful in web applications that harness some of the newer bleeding edge concepts. With the browser type and version you can notify users about challenges they may experience and suggest they upgrade before using such application. Not a great idea on a large scale public site; but on a private application this type of check can be helpful.
Searching for a way to do this at the PHP layer and not at the client layer was more of a challenge than I would have guessed; the only script available was written by Gary White and Gary no longer maintains this script because of reliability. I do agree 100% with Gary about the readability; however, there are realistic reasons to desire the user’s browser and browser version and if your visitor is not echoing a false user agent we can take an educated guess.
Check out the script and find out more information on the link below