Detecting Chrome OS with Javascript

Question

I want to detect Chrome OS with Javascript, and I'm using navigator.userAgent for this. Now, I'm running Chrome OS, and my navigator userAgent is

Mozilla/5.0 (X11; CrOS armv7l 6680.78.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.102 Safari/537.36

Now. I used Regular Expressions to check for the style of the userAgent, and wrote the code below.

<script>
    if ( navigator.userAgent = /^Mozilla\/\d{1}^.\d{1}^(X11; CrOS i\d{3} \d{1}^.\d{2}\d{3} ^AppleWebKit\/\d{3}^.\d{2} ^(KHTML, like Gecko) Chrome\/ \d{2}^.\d{1}^.\d{3}^.\d{2} ^Safari\/\d{3}^\d{2}/ ){
      console.log(navigator.userAgent);
    } else {
      console.log(navigator.userAgent);
    }
</script>

Now, upon loading this Script, I get an error.

Uncaught SyntaxError: Invalid regular expression: /^Mozilla\/\d{1}^.\d{1}^(X11; CrOS i\d{3} \d{1}^.\d{2}\d{3} ^AppleWebKit\/\d{3}^.\d{2} ^(KHTML, like Gecko) Chrome\/ \d{2}^.\d{1}^.\d{3}^.\d{2} ^Safari\/\d{3}^\d{2}/: Unterminated group

What is wrong here with my code?

Before you write more code that looks at the user agent, you might want to consider using [feature detection](http://www.jibbering.com/faq/faq_notes/not_browser_detect.html) instead. We, of course, could only help you with feature detection if you described the actual problem you're trying to solve with Chrome OS. — jfriend00, Apr 15 '15 at 17:47
@jfriend00 Thank you for the advise, of using feature detection, and I'm sure I'll be using that link later on, but for this web application, I would rather look at the user agent. — FoxInFlame, Apr 15 '15 at 18:03
@jfriend00 I think so because Chrome OS is essentially just the Chrome Browser. I want to detect the OS, and not the browser type. Correct me if I'm wrong. — FoxInFlame, Apr 15 '15 at 19:09
Until you tell us why you're trying to detect Chrome OS (e.g. what the real problem is here), we can't really have a meaningful conversation about using feature detection instead. You're asking about a particular solution you've selected rather than telling us the real problem you're trying to solve which is a common way people limit themselves here on SO. — jfriend00, Apr 15 '15 at 19:17
@jfriend00 Proprietary applications. Maybe he is trying to make the next Google. Do you want chunk of that? The q is useful for me..... — jeffbRTC, Feb 19 '21 at 09:57

score 13 · Accepted Answer · edited May 23 '17 at 11:46

What it's complaining about is that you have an ( with no matching ). In a regular expression, ( and ) define capture groups and have to be balanced. If you want to match an actual ( or ), you have to escape it with a backslash.

But there are several other issues. It doesn't make sense to have ^ ("beginning of input") anywhere but the beginning of the expression, for instance.

But I don't think anything else puts CrOS in the user agent, so perhaps simply:

if (/\bCrOS\b/.test(navigator.userAgent)) {
    // yes, it is (probably, if no one's mucked about with their user agent string)
} else {
    // No, it isn't (probably, if no one's mucked about with their user agent string)
}

The \b are "word boundaries" so we don't match that string in the middle of a word. Note that I left it case-sensitive.

Side note: I find https://regex101.com/#javascript (which I am not in any way affiliated with) quite useful for debugging regular expressions.

Side note #2: The above is useful if you really do need to detect ChromeOS, but if it's just a feature you need to check for, as jfriend00 points out, feature detection may be the better way to go.

Thank you for a very explained answer to my question, plus links that I had never even seen before. I will prefer to go with user agent, than feature detection for this time. — FoxInFlame, Apr 15 '15 at 18:15

bytecode77 · Answer 2 · 2015-04-15T17:57:40.363

7

How about this?

var chromeOS = /(CrOS)/.test(navigator.userAgent);

Because a Chrome OS user agent looks like this:

Mozilla/5.0 (X11; CrOS i686 0.12.433) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.77 Safari/534.30

And filtering out "CrOS" is a good solution.

edited Apr 15 '15 at 17:57

answered Apr 15 '15 at 17:48

bytecode77

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What is the g standing for, and what is it used for in your example? – FoxInFlame Apr 15 '15 at 17:55
It's a global modifier, finding all matches and not just the first one. But I guess it can be removed here, see my edited answer. – bytecode77 Apr 15 '15 at 17:58
1

There's also no purpose to using a capture group if you're going to use `.test`. – T.J. Crowder Apr 15 '15 at 18:08

score 4 · Answer 3 · answered Feb 06 '21 at 21:07

I Use This:

It's pretty simple and you can avoid regex. You could add more agents if you wanted to.

// Detect if the OS is Windows or Chrome OS

var detectedOS;

if (window.navigator.userAgent.indexOf("Windows") != -1) {detectedOS = "Windows";}
if (window.navigator.userAgent.indexOf("CrOS") != -1) {detectedOS = "Chrome";}

alert("detectedOS: " + detectedOS);

Detecting Chrome OS with Javascript

3 Answers3

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