获得当前日期所属的本周第一天与最后一天

echo '<br>本周起始时间:<br>';
echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m"),date("d")-date("w")+1,date("Y")))," ";
echo date("Y-m-d H:i:s",mktime(23,59,59,date("m"),date("d")-date("w")+7,date("Y")))," ";