Detecting Device Type in a web application: Mobile, Tablet or Desktop

To check whether the request is coming from mobile, tablet or desktop.

function detectDevice() {
	$tablet_browser = 0;
	$mobile_browser = 0;
	
	if (preg_match('/(tablet|ipad|playbook)|(android(?!.*(mobi|opera mini)))/i', strtolower($_SERVER['HTTP_USER_AGENT']))) {
		$tablet_browser++;
	}
	
	if (preg_match('/(up.browser|up.link|mmp|symbian|smartphone|midp|wap|phone|android|iemobile)/i', strtolower($_SERVER['HTTP_USER_AGENT']))) {
		$mobile_browser++;
	}
	
	if ((strpos(strtolower($_SERVER['HTTP_ACCEPT']),'application/vnd.wap.xhtml+xml') > 0) or ((isset($_SERVER['HTTP_X_WAP_PROFILE']) or isset($_SERVER['HTTP_PROFILE'])))) {
		$mobile_browser++;
	}
	
	$mobile_ua = strtolower(substr($_SERVER['HTTP_USER_AGENT'], 0, 4));
	$mobile_agents = array(
		'w3c ','acs-','alav','alca','amoi','audi','avan','benq','bird','blac',
		'blaz','brew','cell','cldc','cmd-','dang','doco','eric','hipt','inno',
		'ipaq','java','jigs','kddi','keji','leno','lg-c','lg-d','lg-g','lge-',
		'maui','maxo','midp','mits','mmef','mobi','mot-','moto','mwbp','nec-',
		'newt','noki','palm','pana','pant','phil','play','port','prox',
		'qwap','sage','sams','sany','sch-','sec-','send','seri','sgh-','shar',
		'sie-','siem','smal','smar','sony','sph-','symb','t-mo','teli','tim-',
		'tosh','tsm-','upg1','upsi','vk-v','voda','wap-','wapa','wapi','wapp',
		'wapr','webc','winw','winw','xda ','xda-');
	 
	if (in_array($mobile_ua,$mobile_agents)) {
		$mobile_browser++;
	}

	if (strpos(strtolower($_SERVER['HTTP_USER_AGENT']),'opera mini') > 0) {
		$mobile_browser++;
		//Check for tablets on opera mini alternative headers
		$stock_ua = strtolower(isset($_SERVER['HTTP_X_OPERAMINI_PHONE_UA']) ? $_SERVER['HTTP_X_OPERAMINI_PHONE_UA'] : (isset($_SERVER['HTTP_DEVICE_STOCK_UA']) ? $_SERVER['HTTP_DEVICE_STOCK_UA'] : ''));
		if (preg_match('/(tablet|ipad|playbook)|(android(?!.*mobile))/i', $stock_ua)) {
			$tablet_browser++;
		}
	}
	 
	if ($tablet_browser > 0) {
	   $device = 'tablet';
	} else if ($mobile_browser > 0) {
	   $device = 'mobile';
	} else {
	   $device = 'desktop';
	}
	return $device;
}

Now call this function wherever you need it.

echo detectDevice();