array_compare_recursive

if (!(is_array($a1) and (is_array($a2)))) { return FALSE;}

   if (!count($a1) == count($a2))
      {
       return FALSE; // arrays don't have same number of entries
      }

   foreach ($a1 as $key => $val)
   {
       if (!array_key_exists($key, $a2))
           {return FALSE; // uncomparable array keys don't match
              }
       elseif (is_array($val) and is_array($a2[$key]))  // if both entries are arrays then compare recursive
           {if (!array_compare_recursive($val,$a2[$key])) return FALSE;
           }
       elseif (!($val === $a2[$key])) // compare entries must be of same type.
           {return FALSE;
           }
   }
   return TRUE; // $a1 === $a2