The calendar that PHP implements

The calendar effects are shown below:

calendar.class.php

<?php class Calendar {private $year;//Current year private $month;//Current Month private $start _wee KDAY; The first day of the month corresponds to the week a few private $days; What is the total number of days of the current month function __construct () {$this->year=isset ($_get["year")? $_get["Year"]: DA  
            Te ("Y"); $this->month=isset ($_get["month"])?  
                  
            $_get["Month"]: Date ("M");  
            $this->start_weekday=date ("W", Mktime (0, 0, 0, $this->month, 1, $this->year));  
        $this->days=date ("T", mktime (0, 0, 0, $this->month, 1, $this->year));  
            function out () {echo ' <table align= ' center > ';  
            $this->chagedate ("test.php");  
            $this->weekslist ();  
            $this->dayslist ();  
        Echo ' </table> ';  
      
            Private Function Weekslist () {$week =array (' Day ', ' one ', ' two ', ' three ', ' four ', ' five ', ' six '); Echo ' <tr>'; For ($i =0 $i <count ($week); $i + +) echo ' <th class= ' fontb ' > '. $week [$i]. '  
      
            </th> ';  
        Echo ' </tr> ';  
            Private Function Dayslist () {echo ' <tr> '; Output spaces (to be vacated before the first day of January) for ($j =0; $j < $this->start_weekday; $j + +) echo ' <td> <  
      
      
            /TD> ';  
                For ($k =1 $k <= $this->days; $k + +) {$j + +;  
                if ($k ==date (' d ')) echo ' <td class= ' fontb ' > '. $k. ' </td> ';  
      
                else echo ' <td> '. $k. ' </td> ';  
                      
            if ($j%7==0) echo ' </tr><tr> ';  
                }//Next few spaces while ($j%7!==0) {echo ' <td> </td> ';  
            $j + +; } Echo ' </tr>';  
                  
            Private Function Prevyear ($year, $month) {$year = $year-1;  
      
            if ($year < 1970) $year = 1970;     
        Return "year={$year}&month={$month}"; Private Function Prevmonth ($year, $month) {if ($month = = 1) {$ye  
              
                AR = $year-1;  
      
                if ($year < 1970) $year = 1970;  
            $month = 12;  
            }else{$month--;     
        Return "year={$year}&month={$month}";  
      
            Private Function Nextyear ($year, $month) {$year = $year + 1;  
      
            if ($year > 2038) $year = 2038;     
        Return "year={$year}&month={$month}"; }//Url:http://www.bianceng.cn/webkf/php/201410/45945.htm PRivate function Nextmonth ($year, $month) {if ($month ==12) {$year + +;  
      
                if ($year > 2100) $year = 2100;  
            $month = 1;  
            }else{$month + +;     
        Return "year={$year}&month={$month}";  
            Private Function chagedate ($url = "") {echo ' <tr> '; Echo ' <td><a href= '. $this->prevyear ($this->year, $this->month). " > '. ' << '. '  
            </a></td> '; Echo ' <td><a href= '. $this->prevmonth ($this->year, $this->month). " > '. ' < '. '  
            </a></td> ';  
            Echo ' <td colspan= 3 ' > ';  
            Echo ' <form> '; Echo ' <select name= ' year ' onchange= ' window.location=\ '. $url. Year=\ ' +this.options[selectedindex].value+\ ' &month= '. $this->month. ' 
            \ ' > '; For($sy =1970; $sy <= 2100; $sy + +) {$selected = ($sy = = $this->year)?  
                "Selected": ""; Echo ' <option '. $selected. ' value= '. $sy. ' " > '. $sy. '  
            </option> ';  
            Echo ' </select> '; Echo ' <select name= ' month ' onchange= ' window.location=\ '. $url. ' Year= '. $this->year. '
            &month=\ ' +this.options[selectedindex].value ' > '; For ($sm =1 $sm <=12; $sm + +) {$selected 1 = ($sm = = $this->month)?  
                "Selected": "";  
            Echo ' <option '. $selected 1. ' value= '. $sm. ' > ' $sm. ' </option> ';  
            Echo ' </select> ';     
            Echo ' </form> ';  
      
      
            Echo ' </td> '; Echo ' <td><a href= '. $this->nextyear ($this->year, $this->month). " > '. ' >> '. '  
            </a></td> '; Echo ' <td><a href= '. $this->nextmonth ($this->year, $this->month). ' " > '. ' > '. '  
            </a></td> ';  
        Echo ' </tr> '; }}?>

test.php