方法

function getmonsun(){
    $curtime = time();
    $curweekday = date('w');
    //为0是 就是 星期七
    $curweekday = $curweekday?$curweekday:7;
    
    
    $curmon = $curtime - ($curweekday-1)*86400;
    $cursun = $curtime + (7 - $curweekday)*86400;
    
    $cur['mon'] = $curmon;
    $cur['sun'] = $cursun;
     
    return $cur;
}
$cur = getmonsun();
 
echo date('Y-m-d',$cur['mon']);
echo "<br>";
echo date('Y-m-d',$cur['sun']);
}