php获取本周的开始、结束时间戳

$n = date("Y-m-d");
$w=date('w',strtotime($n));
$beginweek=strtotime("$n -".($w ? $w - 1 : 6).'     days');
$endweek=$beginweek + 86400*7-1;
echo $beginweek;
echo $endweek;