Creation of weekly calender in php

Creation of weekly calender in php

I have created a php calender which will show one week at a time.Here is
the code i have created
<?php
$week = date("W");
$year = (isset($_GET['year']))?$_GET['year']:date("Y");
$week = (isset($_GET['week']))?$_GET['week']:Date('W');
if($week>53){
$year+= 1;
$week=1;}
?>
<a href="<?php echo
$_SERVER['PHP_SELF'].'?week='.($week+1).'&year='.$year; ?>">Next Week</a>
<!--Next week-->
<a href="<?php echo
$_SERVER['PHP_SELF'].'?week='.($week-1).'&year='.$year; ?>">Pre Week</a>
<!--Previous week-->
<table border="1px">
<tr>
<td>Employee</td>
<?php
for($day=1; $day<=7; $day++)
{
$d = strtotime($year."W".$week.$day);
echo "<td>".date('l',$d )."<br>";
echo date('d M',$d)."</td>";
}
?>
</tr>
when i am trying to go to the next week it is working correctly. But when
the year is changing it is not working for the next year.