Browser detection in Javascript --- ERROR?

Question

This is the detector: http://w3schools.com/js/tryit.asp?filename=try_nav_all

In Chrome, Firefox, Safari and Netscape it always shows the browser codename as Mozilla, and the browser name as Netscape. Shouldn't this change according to the browser?

Here is the code and the different outputs, if you're interested:

CODE:

document.write("Browser CodeName: " + navigator.appCodeName);
document.write("<br /><br />");
document.write("Browser Name: " + navigator.appName);
document.write("<br /><br />");
document.write("Browser Version: " + navigator.appVersion);
document.write("<br /><br />");
document.write("Cookies Enabled: " + navigator.cookieEnabled);
document.write("<br /><br />");
document.write("Platform: " + navigator.platform);
document.write("<br /><br />");
document.write("User-agent header: " + navigator.userAgent);

CHROME OUTPUT:

Browser CodeName: Mozilla

Browser Name: Netscape

Browser Version: 5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10

Cookies Enabled: true

Platform: Win32

User-agent header: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10

FIREFOX OUTPUT:

Browser CodeName: Mozilla

Browser Name: Netscape

Browser Version: 5.0 (Windows; es-ES)

Cookies Enabled: true

Platform: Win32

User-agent header: Mozilla/5.0 (Windows; U; Windows NT 6.1; es-ES; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 

SAFARI OUTPUT:

Browser CodeName: Mozilla

Browser Name: Netscape

Browser Version: 5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.19.4 (KHTML, like Gecko) Version/5.0.3 Safari/533.19.4

Cookies Enabled: true

Platform: Win32

User-agent header: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.19.4 (KHTML, like Gecko) Version/5.0.3 Safari/533.19.4

NETSCAPE OUTPUT:

Browser CodeName: Mozilla

Browser Name: Netscape

Browser Version: 5.0 (Windows; en-US)

Cookies Enabled: true

Platform: Win32

User-agent header: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax)

Answer 1

Perhaps it should, it depends on what they're trying to achieve.

But it just demonstrates why browser detection has fallen into disrepute, in favor of feature detection. Browser detection code ages incredibly quickly. Feature detection, on the other hand, is fairly timeless.

For example: I could check to see if the browser is IE and, if so, assume that the browser doesn't have Array.prototype.indexOf. But then IE9 comes along and adds it, but like a mug I'm still using my own version because I think "IE" doesn't have it. Much better to actually check to see if it exists in the implementation I'm running on, without much caring what brand it is. And of course, feature detection will work with a browser I've never heard of; browser detection will fail and fall back on some completely-arbirary "default".

Sometimes it's not as straight-forward as doing an if (Array.prototype.indexOf), but it's usually possible. Juriy Zaytsev (kangax) has a great list of feature detection stuff.

(Side note: Nearly all browsers claim (at some level) that they're "Mozilla", because some sites easly on preferred Netscape browsers (yes, that long ago) to Microsoft ones, and were doing browser detection to check.)