php 日期函数

";     
echo "今天:",date("Y-m-d",strtotime("18 june 2008")),"
";     
echo "昨天:",date("Y-m-d",strtotime("-1 day")), "
";     
echo "明天:",date("Y-m-d",strtotime("+1 day")), "
";     
echo "一周后:",date("Y-m-d",strtotime("+1 week")), "
";     
echo "一周零两天四小时两秒后:",date("Y-m-d G:H:s",strtotime("+1 week 2 days 4 hours 2 seconds")), "
";     
echo "下个星期四:",date("Y-m-d",strtotime("next Thursday")), "
";     
echo "上个周一:".date("Y-m-d",strtotime("last Monday"))."
";     
echo "一个月前:".date("Y-m-d",strtotime("last month"))."
";     
echo "一个月后:".date("Y-m-d",strtotime("+1 month"))."
";     
echo "十年后:".date("Y-m-d",strtotime("+10 year"))."
";     
?>

php判断一个日期距今天还有多少天