[javascript] Browser detection in JavaScript?

I make this small function, hope it helps. Here you can find the latest version browserDetection

function detectBrowser(userAgent){
  var chrome  = /.*(Chrome\/).*(Safari\/).*/g;
  var firefox = /.*(Firefox\/).*/g;
  var safari  = /.*(Version\/).*(Safari\/).*/g;
  var opera   = /.*(Chrome\/).*(Safari\/).*(OPR\/).*/g

  if(opera.exec(userAgent))
    return "Opera"
  if(chrome.exec(userAgent))
    return "Chrome"
  if(safari.exec(userAgent))
    return "Safari"
  if(firefox.exec(userAgent))
    return "Firefox"
}