Why is browser sniffing not a recommended practice?

Question

You hear it all over the place: using javascript to sniff the user agent string to detect browser versions is a Very Bad Thing. The latest version of jQuery has now deprecat

Answer 1

Sniff for features, not for useragents. Pseudocode:

if (browser.supports('feature')){
    //execute feature
}

else{
    //fallback
}