(php)实现万年历

  <?php
 //修改页面编码
 header("content-type:text/html;charset=utf-8");

 //获取当前年
 $year=$_GET['y']?$_GET['y']:date('Y');

 //获取当年月
 $month=$_GET['m']?$_GET['m']:date('m');

 //获取当前月多少天
 $days=date('t',strtotime("{$year}-{$month}-1"));

 //当前一号周几
 $week=date('w',strtotime("{$year}-{$month}-1"));

 //居中
 echo "<center>";

 //计算上个月
 if($month==1)
 {
     $prevyear=$year-1;
     $prevmonth=12;
 }
 else
 {
     $prevyear=$year;
     $prevmonth=$month-1;
 }

 //计算下个月
 if($month==12)
 {
     $nextyear=$year+1;
     $nextmonth=1;
 }
 else
 {
     $nextyear=$year;
     $nextmonth=$month+1;
 }

 //输出表头
 echo " <h2><a href='万年历.php?y={$prevyear}&m={$prevmonth}'>上一月</a>|{$year}年{$month}月|<a  href='万年历.php?y={$nextyear}&m={$nextmonth}'>下一月</a></h2>";

 //输出日期表格
 echo "<table width='700px' border='1px'>";
 echo "<tr>";
 echo "<th>周日</th>";
 echo "<th>周一</th>";
 echo "<th>周二</th>";
 echo "<th>周三</th>";
 echo "<th>周四</th>";
 echo "<th>周五</th>";
 echo "<th>周六</th>";
 echo "</tr>";

 //铺表格
 for ($i=1-$week; $i <=$days ;)
      {
         echo "<tr>";
         for ($j=0; $j < 7; $j++)
          {
             if ($i>$days || $i<1)
             {
                 echo "<td>&nbsp;</td>";
             }
             else
             {
                  echo "<td>{$i}</td>";
             }
             $i++;
         }
         echo "</tr>";
     }
 echo "</table>";
 echo "</center>";

 ?>