/^ 0*?(?:1?\d\d?|2[0-4]\d|25[0-5])\. 0*?(?:1?\d\d?|2[0-4]\d|25[0-5])\. 0*?(?:1?\d\d?|2[0-4]\d|25[0-5])\. 0*?(?:1?\d\d?|2[0-4]\d|25[0-5]) $/x;