It's all about what you really want to do, but in times to come and right now, the best way is avoid browser detection and check for features. like Canvas, Audio, WebSockets, etc through simple javascript calls or in your CSS, for me your best approach is use a tool like ModernizR:
Unlike with the traditional—but highly unreliable—method of doing “UA sniffing,” which is detecting a browser by its (user-configurable) navigator.userAgent
property, Modernizr does actual feature detection to reliably discern what the various browsers can and cannot do.
If using CSS, you can do this:
.no-js .glossy,
.no-cssgradients .glossy {
background: url("images/glossybutton.png");
}
.cssgradients .glossy {
background-image: linear-gradient(top, #555, #333);
}
as it will load and append all features as a class name in the <html>
element and you will be able to do as you wish in terms of CSS.
And you can even load files upon features, for example, load a polyfill js and css if the browser does not have native support
Modernizr.load([
// Presentational polyfills
{
// Logical list of things we would normally need
test : Modernizr.fontface && Modernizr.canvas && Modernizr.cssgradients,
// Modernizr.load loads css and javascript by default
nope : ['presentational-polyfill.js', 'presentational.css']
},
// Functional polyfills
{
// This just has to be truthy
test : Modernizr.websockets && window.JSON,
// socket-io.js and json2.js
nope : 'functional-polyfills.js',
// You can also give arrays of resources to load.
both : [ 'app.js', 'extra.js' ],
complete : function () {
// Run this after everything in this group has downloaded
// and executed, as well everything in all previous groups
myApp.init();
}
},
// Run your analytics after you've already kicked off all the rest
// of your app.
'post-analytics.js'
]);
a simple example of requesting features from javascript:
http://jsbin.com/udoyic/1