Summary
for($year = 2004; $year < 2014; $year++){
$isLeapYear = checkdate(2, 29, $year) ? "leap year" : "not leap year";
echo "{$year} is {$isLeapYear}.\n";
}Reference
ほでなすPHP - 関数ミニリファレンス -> 日付・時刻関数http://www.shigeweb.jp/php/project_p/?section=miniref&page=date#checkdate
checkdate
http://php.s3.to/man/function.checkdate.html