$days = array('日','一','二','三','四','五','六');
$today = date('w')-1;$this_monday = strtotime('-'.$today.' day');
echo "今天是:星期",$days[$today],"<br></br>本週一:",date('Y-m-d',$this_monday),"<br></br>下週一:",date('Y-m-d',strtotime('+1 week',$this_monday));
//結果如下:
//今天是:星期四
//本週一:2011-10-10
//下週一:2011-10-17