$content = ob_get_contents();这句代码怎么理解
<?php
setcookie('test', time());
ob_start();
print_r($_COOKIE);
$content = ob_get_contents();
$content = str_replace(" ", ' ', $content);
ob_clean();
header("content-type:text/html; charset=utf-8");
echo '当前的Cookie为：<br>';
echo nl2br($content);
