<?php
header("Content-type: text/html; charset=utf-8"); 
    function   get_week($date){
        //強制轉換日期格式
        $date_str=date('Y-m-d',strtotime($date));
        //封裝成陣列
        $arr=explode("-", $date_str);
        //引數賦值
        //年
        $year=$arr[0];
        //月，輸出2位整型，不夠2位右對齊
        $month
 
=sprintf('%02d',$arr[1]);
        //日，輸出2位整型，不夠2位右對齊
        $day=sprintf('%02d',$arr[2]);
        //時分秒預設賦值為0；
        $hour = $minute = $second = 0;   
        //轉換成時間戳
        $strap = mktime($hour,$minute,$second,$month,$day,$year);
        //獲取數字型星期幾
        $number_wk=date("w",$strap);
        //自定義星期陣列
        $weekArr
 
=array("星期日","星期一","星期二","星期三","星期四","星期五","星期六");
        //獲取數字對應的星期
        return $weekArr[$number_wk];
    }

    //測試
    $date="2016-08-21";
    echo get_week($date);