isMobile

A simple JS library that detects mobile devices.

Big thanks to Igor Ribeio Lima for his contributions.

Why use isMobile?

I had a specific requirement for a project when I created this:

- Redirect all iPhones, iPods, Android phones, and seven inch devices to the mobile site.

A completely separate site had been created for mobile devices, so feature detection/graceful degredation/progressive enhancement were out of the question. I had to redirect.

I couldn't do detection on the back-end, because the entire site was cached and served by Akamai; I had to do the detection client-side.

So I resorted to UA sniffing.

I tried to keep the script small (currently ~1.3k bytes, minified) and simple, because it would need to execute in the <head>, which is generally a bad idea, since JS blocks downloading and rendering of anything else while it parses and executes. In the case of mobile redirection, I don't mind so much, because I want to start the redirect as soon as possible, before the device has a chance to start downloading and rendering stuff. For non-mobile platforms, the script should execute fast, so the browser can quickly get back to downloading and rendering.

How it works

isMobile runs quickly on page load to detect mobile devices; it then creates a JavaScript object with the results.

Devices detected by isMobile

The following properies of the isMobile object will either be true or false

Apple devices

isMobile.apple.phone
isMobile.apple.ipod
isMobile.apple.tablet
isMobile.apple.device (any mobile Apple device)

Android devices

isMobile.android.phone
isMobile.android.tablet
isMobile.android.device (any mobile Android device)

Windows devices

isMobile.windows.phone
isMobile.windows.tablet
isMobile.windows.device (any mobile Windows device)

Specific seven inch devices

isMobile.seven_inch
- true if the device is one of the following 7" devices:
  - Nexus 7
  - Kindle Fire
  - Nook Tablet 7 inch
  - Galaxy Tab 7 inch

"Other" devices

isMobile.other_blackberry_10
isMobile.other_blackberry
isMobile.other_opera (Opera Mini)
isMobile.other_firefox

Aggregate Groupings

isMobile.any - any device matched
isMobile.phone - any device in the 'phone' groups above
isMobile.tablet - any device in the 'tablet' groups above

Example Usage

I include the minified version of the script, inline, and at the top of the <head>. Cellular connections tend to suck, so it would be wasteful overhead to open another connection, just to download <1kb of JS:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <script>
        // Minified version of isMobile included in the HTML since it's <1kb
        (function(i){var e=/iPhone/i,n=/iPod/i,o=/iPad/i,t=/(?=.*\bAndroid\b)(?=.*\bMobile\b)/i,r=/Android/i,d=/BlackBerry/i,s=/Opera Mini/i,a=/IEMobile/i,b=/(?=.*\bFirefox\b)(?=.*\bMobile\b)/i,h=RegExp("(?:Nexus 7|BNTV250|Kindle Fire|Silk|GT-P1000)","i"),c=function(i,e){return i.test(e)},l=function(i){var l=i||navigator.userAgent;this.apple={phone:c(e,l),ipod:c(n,l),tablet:c(o,l),device:c(e,l)||c(n,l)||c(o,l)},this.android={phone:c(t,l),tablet:!c(t,l)&&c(r,l),device:c(t,l)||c(r,l)},this.other={blackberry:c(d,l),opera:c(s,l),windows:c(a,l),firefox:c(b,l),device:c(d,l)||c(s,l)||c(a,l)||c(b,l)},this.seven_inch=c(h,l),this.any=this.apple.device||this.android.device||this.other.device||this.seven_inch},v=i.isMobile=new l;v.Class=l})(window);


        // My own arbitrary use of isMobile, as an example
        (function () {
            var MOBILE_SITE = '/mobile/index.html', // site to redirect to
                NO_REDIRECT = 'noredirect'; // cookie to prevent redirect

            // I only want to redirect iPhones, Android phones and a handful of 7" devices
            if (isMobile.apple.phone || isMobile.android.phone || isMobile.seven_inch) {

                // Only redirect if the user didn't previously choose
                // to explicitly view the full site. This is validated
                // by checking if a "noredirect" cookie exists
                if ( document.cookie.indexOf(NO_REDIRECT) === -1 ) {
                    document.location = MOBILE_SITE;
                }
            }
        })();
    </script>
</head>
<body>
    <!-- imagine lots of html and content -->
</body>
</html>

node.js usage

#####Installation npm install ismobilejs

#####Usage

var isMobile = require('ismobilejs');
console.log(isMobile(req.headers['user-agent']).any);

digitalismic/isMobile