Creation of weekly calender in php - php

Question

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;
$week=1;
}
?>
Next Week <!--Next week-->
Pre Week <!--Previous week-->
<table border="1px">
<tr>
<td>Employee</td>
<?php
for($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.

Answer 1

Leave the week calculation to the DateTime::setIsoDate() method.
Here is the simplest and best solution for your problem :
<?php
$dt = new DateTime;
if (isset($_GET['year']) && isset($_GET['week'])) {
$dt->setISODate($_GET['year'], $_GET['week']);
} else {
$dt->setISODate($dt->format('o'), $dt->format('W'));
}
$year = $dt->format('o');
$week = $dt->format('W');
?>
Pre Week <!--Previous week-->
Next Week <!--Next week-->
<table>
<tr>
<td>Employee</td>
<?php
do {
echo "<td>" . $dt->format('l') . "<br>" . $dt->format('d M Y') . "</td>\n";
$dt->modify('+1 day');
} while ($week == $dt->format('W'));
?>
</tr>
</table>

Answer 2

When you're using strtotime, your week has to be two-digit. You have to prepend a zero, if the week is lower than 10 before the for loop.
if($week < 10) {
$week = '0'. $week;
}
for($day = 1; $day <= 7; $day++) {
Also, a year only has 52 weeks, the condition at the beginning should be.
if($week > 52) {
$year++;
$week = 1;
} elseif($week < 1) { // If you want the possibility to go back too
$year--;
$week = 52;
}
Full code:
<?php
$year = (isset($_GET['year'])) ? $_GET['year'] : date("Y");
$week = (isset($_GET['week'])) ? $_GET['week'] : date('W');
if($week > 52) {
$year++;
$week = 1;
} elseif($week < 1) {
$year--;
$week = 52;
}
?>
Next Week <!--Next week-->
Pre Week <!--Previous week-->
<table border="1px">
<tr>
<td>Employee</td>
<?php
if($week < 10) {
$week = '0'. $week;
}
for($day= 1; $day <= 7; $day++) {
$d = strtotime($year ."W". $week . $day);
echo "<td>". date('l', $d) ."<br>". date('d M', $d) ."</td>";
}
?>
</tr>
</table>