PHP Calendar

Calendar Functions

<?php
$days = cal_days_in_month(
  CAL_GREGORIAN, 2, 2024
);
?>

<?php
$info = cal_info(
  CAL_GREGORIAN
);
?>

<?php
$cal = cal_from_jd(
  cal_to_jd(CAL_GREGORIAN, 3, 10, 2025),
  CAL_GREGORIAN
);
?>

<?php
$jd = cal_to_jd(
  CAL_GREGORIAN, 3, 10, 2025
);
?>

🔹 Simple Calendar Display

Create a basic calendar display showing the current month. This example uses date functions to determine the month layout and displays it in a table.

<?php
$month = date('m');
$year = date('Y');
$monthName = date('F', mktime(0, 0, 0, $month, 1, $year));

echo "<h3>$monthName $year</h3>";
echo "<table border='1'>";
echo "<tr><th>Sun</th><th>Mon</th><th>Tue</th><th>Wed</th><th>Thu</th><th>Fri</th><th>Sat</th></tr>";

$daysInMonth = cal_days_in_month(CAL_GREGORIAN, $month, $year);
$firstDay = date('w', mktime(0, 0, 0, $month, 1, $year));

echo "<tr>";
for($i = 0; $i < $firstDay; $i++) {
    echo "<td></td>";
}

for($day = 1; $day <= $daysInMonth; $day++) {
    echo "<td>$day</td>";
    if(($day + $firstDay) % 7 == 0) {
        echo "</tr><tr>";
    }
}
echo "</tr></table>";
?>

🔹 Days in Month Function

The cal_days_in_month() function returns the number of days in a specified month and year. Useful for validating dates and creating calendars.

<?php
// Get days in different months
$jan = cal_days_in_month(CAL_GREGORIAN, 1, 2025);
$feb = cal_days_in_month(CAL_GREGORIAN, 2, 2025);
$febLeap = cal_days_in_month(CAL_GREGORIAN, 2, 2024);

echo "January 2025: " . $jan . " days<br>";
echo "February 2025: " . $feb . " days<br>";
echo "February 2024 (leap): " . $febLeap . " days<br>";

// Check current month
$currentMonth = date('n');
$currentYear = date('Y');
$daysThisMonth = cal_days_in_month(CAL_GREGORIAN, $currentMonth, $currentYear);
echo "This month has: " . $daysThisMonth . " days";
?>

🔹 Calendar Information

The cal_info() function returns information about a calendar system including month names, day names, and calendar properties for localization.

<?php
// Get Gregorian calendar info
$info = cal_info(CAL_GREGORIAN);

echo "Calendar: " . $info['calname'] . "<br>";
echo "Abbreviation: " . $info['calsymbol'] . "<br><br>";

echo "Months:<br>";
foreach($info['months'] as $num => $name) {
    echo "$num: $name<br>";
    if($num == 3) break; // Show first 3 months
}

echo "<br>Days:<br>";
foreach($info['abbrevdaynames'] as $num => $name) {
    echo "$num: $name<br>";
    if($num == 2) break; // Show first 3 days
}
?>

🔹 Dynamic Month Selector

Create an interactive calendar that allows users to select different months and years. This example demonstrates building a month navigation system.

<?php
// Get month and year from URL or use current
$month = isset($_GET['month']) ? $_GET['month'] : date('m');
$year = isset($_GET['year']) ? $_GET['year'] : date('Y');

$monthName = date('F', mktime(0, 0, 0, $month, 1, $year));
$daysInMonth = cal_days_in_month(CAL_GREGORIAN, $month, $year);

// Previous and next month links
$prevMonth = $month - 1;
$prevYear = $year;
if($prevMonth < 1) {
    $prevMonth = 12;
    $prevYear--;
}

$nextMonth = $month + 1;
$nextYear = $year;
if($nextMonth > 12) {
    $nextMonth = 1;
    $nextYear++;
}

echo "<a href='?month=$prevMonth&year=$prevYear'>&laquo; Previous</a> ";
echo "<strong>$monthName $year</strong> ";
echo "<a href='?month=$nextMonth&year=$nextYear'>Next &raquo;</a><br><br>";
echo "This month has $daysInMonth days";
?>

🔹 Highlight Current Day

Enhance your calendar by highlighting the current day. This makes it easier for users to identify today's date in the calendar view.

<?php
$month = date('m');
$year = date('Y');
$today = date('j');
$daysInMonth = cal_days_in_month(CAL_GREGORIAN, $month, $year);

echo "<h3>" . date('F Y') . "</h3>";
echo "<div style='display: flex; gap: 5px;'>";

for($day = 1; $day <= 10; $day++) {
    if($day == $today) {
        echo "<div style='background: #007cba; color: white; padding: 10px; border-radius: 5px;'>$day</div>";
    } else {
        echo "<div style='background: #f0f0f0; padding: 10px; border-radius: 5px;'>$day</div>";
    }
}
echo "</div>";
?>