I tried some of the ways and then I decided to fill a list manually and do a simple JS check. And in the end the user has to confirm. Because some checks gave false positive or negative.

var isMobile = false; if (/Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini|Opera Mobile|Kindle|Windows Phone|PSP|AvantGo|Atomic Web Browser|Blazer|Chrome Mobile|Dolphin|Dolfin|Doris|GO Browser|Jasmine|MicroB|Mobile Firefox|Mobile Safari|Mobile Silk|Motorola Internet Browser|NetFront|NineSky|Nokia Web Browser|Obigo|Openwave Mobile Browser|Palm Pre web browser|Polaris|PS Vita browser|Puffin|QQbrowser|SEMC Browser|Skyfire|Tear|TeaShark|UC Browser|uZard Web|wOSBrowser|Yandex.Browser mobile/i.test(navigator.userAgent) && confirm('Are you on a mobile device?')) isMobile = true; 

Now, if you want to use jQuery to set the CSS, you could do the following:

$(document).ready(function() { if (isMobile) $('link[type="text/css"]').attr('href', '/mobile.css'); }); 

Since the borders between mobile and fixed devices become fluent and mobile browers are already powerful, checking width and user confirmation will probably be the best for the future (assuming that width in some cases will still be important). Because touches are already converted into mouse-ups and downs.

And concerning the mobile movability, I suggest you to think about Yoav Barnea's idea:

if(typeof window.orientation !== 'undefined'){...} 

I tried some of the ways and then I decided to fill a list manually and do a simple JS check. And in the end the user has to confirm. Because some checks gave false positive or negative.

var isMobile = false; if (/Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini|Opera Mobile|Kindle|Windows Phone|PSP|AvantGo|Atomic Web Browser|Blazer|Chrome Mobile|Dolphin|Dolfin|Doris|GO Browser|Jasmine|MicroB|Mobile Firefox|Mobile Safari|Mobile Silk|Motorola Internet Browser|NetFront|NineSky|Nokia Web Browser|Obigo|Openwave Mobile Browser|Palm Pre web browser|Polaris|PS Vita browser|Puffin|QQbrowser|SEMC Browser|Skyfire|Tear|TeaShark|UC Browser|uZard Web|wOSBrowser|Yandex.Browser mobile/i.test(navigator.userAgent) && confirm('Are you on a mobile device?')) isMobile = true; 

Now, if you want to use jQuery to set the CSS, you could do the following:

$(document).ready(function() { if (isMobile) $('link[type="text/css"]').attr('href', '/mobile.css'); }); 

Since the borders between mobile and fixed devices become fluent and mobile browers are already powerful, checking width and user confirmation will probably be the best for the future (assuming that width in some cases will still be important). Because touches are already converted into mouse-ups and downs.

And concerning the mobile movability, I suggest you to think about Yoav Barnea's idea:

if(typeof window.orientation !== 'undefined'){...}