Browser Detect in WordPress

wordpress-detect-ie.php

<?php
/**
 * Detect if the browser is Internet Explorer or not
 * @package WordPress
 * @param int $version optional
 * @return Boolean
 */
function is_IE($version = 0)
{
	$flg = false;
	global $is_winIE;
	if(!$is_winIE)
		return $flg;
	switch($version){
		case 6:
			if(preg_match("/compatible; MSIE 6\.0;/", $_SERVER["HTTP_USER_AGENT"]))
				$flg = true;
			break;
		case 7:
			if(preg_match("/compatible; MSIE 7\.0;/", $_SERVER["HTTP_USER_AGENT"]))
				$flg = true;
			break;
		case 8:
			if(preg_match("/MSIE 8\.0/", $_SERVER["HTTP_USER_AGENT"]))
				$flg = true;
			break;
		default:
			$flg = true;
			break;
	}
	return $flg;
}