function detect_mobile()
{
    if(preg_match('/(alcatel|amoi|android|avantgo|blackberry|benq|cell|cricket|docomo|elaine|htc|
iemobile|iphone|ipad|ipaq|ipod|j2me|java|midp|mini|mmp|mobi|motorola|nec-|nokia|palm|panasonic|philips|phone|sagem|sharp|sie-|smartphone|sony|symbian|t-mobile|telus|up\.browser|up\.link|vodafone|wap|webos|wireless|xda|xoom|zte)/i', $_SERVER['HTTP_USER_AGENT']))
        return true;

    else
        return false;
}

if (detect_mobile())
{
   // Init simple editor
}
else
{
   // Init tinyMCE
}