/**
* Test if the current browser runs on a mobile device (smart phone, tablet, etc.)
*
- * @return bool true|false
+ * @staticvar bool $is_mobile
+ *
+ * @return bool
*/
function wp_is_mobile() {
- static $is_mobile;
+ static $is_mobile = null;
- if ( isset($is_mobile) )
+ if ( isset( $is_mobile ) ) {
return $is_mobile;
+ }
if ( empty($_SERVER['HTTP_USER_AGENT']) ) {
$is_mobile = false;