ไม่เข้าใจ การเขียนวันย้อนหลังเลย ผมอยากจะเขียน code php เลียนแบบ ปฏิทิน แต่ว่า โดยปกติแล้ว

<font color="#006600" size="3">
<style type="text/css">
table, td, th
{
border:1px solid green;
}
th
{
background-color:#009900;
color:white;
}
table
{
border-collapse:collapse;
}
table,th, td
{
border: 1px solid black;
}
table,td
{
border-style: groove;
  border-width: 1px;
  border-color: #038ef9;}
</style>
<?php
echo"<table width='5' background='images/bg_header.jpg' boder='1' >";
echo"<tr>";

$d7=$qd[date('d')];
$d8=$d7-
$_month=date('m');
$_month_1=$_month-1;
$_month_2=$_month+1;
echo"$_month_1";
echo"$d7";
$start = mktime(0, 0, 0,$_month_1,27,date('y'));
$end = mktime(0, 0, 0,$_month,26,date('y'));
  $WriteMonth.="</td></tr><tr >";/////////////

  $WriteMonth.="<td align='center' background='images/bg_header.jpg'><B><font color=\"#000066\">อ.</font></B></td>";
  $WriteMonth.="<td align='center' background='images/bg_header.jpg'><B><font color=\"#000066\">จ.</font></B></td>";
  $WriteMonth.="<td align='center' background='images/bg_header.jpg'><B><font color=\"#000066\">อ.</font></B></td>";
  $WriteMonth.="<td align='center' background='images/bg_header.jpg'><B><font color=\"#000066\">พ.</font></B></td>";
  $WriteMonth.="<td align='center' background='images/bg_header.jpg'><B><font color=\"#000066\">พฤ.</font></B></td>";
  $WriteMonth.="<td align='center' background='images/bg_header.jpg'><B><font color=\"#000066\">ศ.</font></B></td>";
  $WriteMonth.="<td align='center' background='images/bg_header.jpg'><B><font color=\"#000066\">ส.</font></B></td>";
  

	   
  $WriteMonth.="</tr>";
  
 $day.="</td></tr><tr bgcolor=\"#00CCFF\">";/////////////
 $day.="<td align='center'><input type='checkbox' size='1' name='d27' value='1'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d28' value='1'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d29' value='1'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d30' value='1'></td>";
  
 $day.="<td align='center'><input type='checkbox' size='1' name='d31' ></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d01' ></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d02''></B></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d03'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d04' ></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d05' ></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d06' ></td>";
  
 $day.="<td align='center'><input type='checkbox' size='1' name='d07' ></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d08' ></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d09'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d10'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d11'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d12'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d13'></td>";
  
 $day.="<td align='center'><input type='checkbox' size='1' name='d14'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d15'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d16'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d17'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d18'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d19'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d20'></td>";
  
 $day.="<td align='center'><input type='checkbox' size='1' name='d21'></B></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d22'></td>";
 $day.="<td align='center'><B><input type='checkbox' size='1' name='d23' ></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d24'></td>";
 $day.="<td align='center'><B><input type='checkbox' size='1' name='d25'></td>";
 $day.="<td align='center'><input type='checkbox' size='1' name='d26'></td>";
	   
 $day.="</tr>";

 $date_second = 24*60*60;

 $qd = array('Sun'=>'อา.', 'Mon'=>'จ.', 'Tue'=>'อ.', 'Wed'=>'พ.', 'Thu'=>'พฤ.', 'Fri'=>'ศ.', 'Sat'=>'ส.');     

$ee="<center><tr><td>Sun</td><td>Mon</td><td>Tue</td><td>Wed</td><td>Thu</td><td>Fri</td><td>Sat</td></tr></center>";
echo"$ee";
	for($d=$start; $d<=$end; $d+=$date_second)
		
 		{
echo"<tr><td></td>";
	  }
	echo '</tr><br><tr>'."\n";
	  
	  
 for($d=$start; $d<=$end; $d+=$date_second)
 		{
		 
        $dateone=date('d',$d);//////แสดงวันที่จากวันที่ 27-26
        $kk=date("l", mktime(24, 60, 60,date('27'),$dateone, date('y'),date('m')));//แปลงตัวเลขเป็นตัวหนังสือแสดง
        $kk2=date("l", mktime(24,60,60,date('26'),$_month,date('m'),date('y')));
    
	echo"<td>$dateone";		
	echo"$kk";
	echo"<input type='checkbox' name='d[]' value='',date('d',$d),' />";

	  }


  


	 
	   echo"</td>";

	  echo"</tr> <br>";
	  echo"</table>";
echo"<table>
 
";
echo "$ddd";
	  	 
?>
</font><br><br><br>