How can you detect the version of a browser?

Question

I\'ve been searching around for code that would let me detect if the user visiting the website has Firefox 3 or 4. All I have found is code to detect the type of browser but

Answer 1

Here is the java version for somemone who whould like to do it on server side using the String returned by HttpServletRequest.getHeader("User-Agent");

It is working on the 70 different browser configuration I used for testing.

public static String decodeBrowser(String userAgent) {
    userAgent= userAgent.toLowerCase();
    String name = "unknown";
    String version = "0.0";
    Matcher userAgentMatcher = USER_AGENT_MATCHING_PATTERN.matcher(userAgent);
    if (userAgentMatcher.find()) {
      name = userAgentMatcher.group(1);
      version = userAgentMatcher.group(2);
      if ("trident".equals(name)) {
        name = "msie";
        Matcher tridentVersionMatcher = TRIDENT_MATCHING_PATTERN.matcher(userAgent);
        if (tridentVersionMatcher.find()) {
          version = tridentVersionMatcher.group(1);
        }
      }
    }
    return name + " " + version;
  }

  private static final Pattern USER_AGENT_MATCHING_PATTERN=Pattern.compile("(opera|chrome|safari|firefox|msie|trident(?=\\/))\\/?\\s*([\\d\\.]+)");
  private static final Pattern TRIDENT_MATCHING_PATTERN=Pattern.compile("\\brv[ :]+(\\d+(\\.\\d+)?)");