Ramoonus

This plugin adds the Modernizr to your WordPress installation. 
Modernizr is a small JavaScript library that detects the availability of native implementations for next-generation web technologies, i.e. features that stem from the HTML5 and CSS3 specifications. Many of these features are already implemented in at least one major browser (most of them in two or more), and what Modernizr does is, very simply, tell you whether the current browser has this feature natively implemented or not.
For documentation visit http://www.modernizr.com/docs/

Modernizr for WordPress

The 2.8.4 version inserts broken javascript link. I posted a message about this in the support section for the plugin and the author has not responded or fixed the problem. Now, any site that I've added this plugin to can be broken if the user runs an update. 

Instead, if you need Modernizr, insert the following into your header.php file just after <?php wp_head(); ?>:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/modernizr/2.8.3/modernizr.min.js"></script>

Doesn't work - Plugin Defunct

This plugin adds the Modernizr to your WordPress installation.

Mindshare Labs, Inc.

MartyThornley

Version 3 adds support for is_tablet(), is_desktop(), and is_browser() as well as numerous bug fixes and code improvements. As of version 3.1.2 automatic updates of browscap.ini are disabeld until we can deal with memory usage issues.
PHP Browser Detection is a WordPress plugin used to detect a user’s browser. It can be used to send conditional CSS files for Internet Explorer, display different content or custom messages anywhere on the page, or to swap out Flash for an image for iPhones.
Template Tags:
Test for specific browsers:
$version is optional. Include a major version number, a single integer – 3,4,5, etc… Or leave it empty to test for any version.
<pre><code><?php if(is_firefox($version)) { /* your code here */ }; ?>

<?php if(is_safari($version)) { /* your code here */ }; ?>

<?php if(is_chrome($version)) { /* your code here */ }; ?>

<?php if(is_opera($version)) { /* your code here */ }; ?>

<?php if(is_ie($version)) { /* your code here */ }; ?>

<?php if(is_browser($name, $version)) { /* your code here */ }; ?>
</code></pre>
Check for mobile, tablet, iPhone, iPad, iPod, etc…
<pre><code><?php if(is_desktop()) { /* your code here */ }; ?>

<?php if(is_tablet()) { /* your code here */ }; ?>

<?php if(is_iphone($version)) { /* your code here */ }; ?>

<?php if(is_ipad($version)) { /* your code here */ }; ?>

<?php if(is_ipod($version)) { /* your code here */ }; ?>

<?php if(is_mobile()) { /* your code here */ }; ?>
</code></pre>
Check for greater than / less than a specific version…
Less than or equal to Firefox 19: 
 < ?php if(is_firefox() && get_browser_version() 
Less than or equal to IE 10: 
 < ?php if(is_ie() && get_browser_version() 
Greater than or equal to Safari 4: 
 = 4) { /* your code here */ }; ?>
these are just a few examples, but this syntax will work for any browser or version.
Check specific versions…
Is the browser IE6?
 
Is the browser IE10?
 
Or you can get all the info and do what you want with it:
Get just the name…
<pre><code><?php $browser_name = get_browser_name(); ?>
</code></pre>
Get the full version number – 3.2, 5.0, etc…
<pre><code><?php $browser_version = get_browser_version(); ?>
</code></pre>
Or get it all in array…
<pre><code><?php $browser_info = php_browser_info(); ?>
</code></pre>
Shortcodes:
Test for specific browsers:
<pre><code>[is_browser name="chrome" version="45"]
You are using Chrome 45 or above.
[/is_browser]
</code></pre>
Output all browser info:
<pre><code>[browser_info]
</code></pre>

PHP Browser Detection

This worked great for us. It deservers a better rating. Thank you!



Very nice

PHP Browser Detection is a WordPress plugin used to detect a user's browser. Please report any bugs on the support forums.

Modernizr for WordPress vs PHP Browser Detection