Вот тут почитайте  http://hghltd.yandex.net/yandbtm?fmode=inject&url=http%3A%2F%2Fforum.swimming.ru%2Findex.php%3Ftopic%3D4087.0&tld=ru&lang=ru&text=%D0%BF%D0%BB%D0%B0%D0%B2%D0%B0%D0%BD%D0%B8%D0%B5%20%D1%81%D0%BE%D1%80%D0%B5%D0%B2%D0%BD%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F%20%D0%BF%D0%BE%20%D0%B4%D0%B2%D0%BE%D0%B5%20%D0%BD%D0%B0%20%D0%B4%D0%BE%D1%80%D0%BE%D0%B6%D0%BA%D0%B5&l10n=ru&mime=html&sign=8c533ab68c4f9c2fcedf32142f295bc6&keyno=0