How To Program a Days Until Message in PHP (or WordPress Shortcode)

If you’re in retail or e-commerce, you’re likely always counting down to the upcoming retail holiday to provide a sense of urgency for your audience. Years ago, I implemented a solution like this for a client and wanted to share how easy it is.

PHP: Days Until

Below is a PHP function where you can pass the month, day, and (optionally), three different messages depending on how many days until the day of the year will arrive.

<?php
// Function to calculate the countdown to a specific date
function countdown_to_day($month, $day, $today_message = "Today is the big day!", $tomorrow_message = "It's happening tomorrow!", $countdown_message = "Only X days left!") {
    // Get the current year
    $current_year = date('Y');

    // Create DateTime objects for today and the target date
    $today = new DateTime();
    $target_date = new DateTime("$current_year-$month-$day");

    // If the target date has passed this year, set it for next year
    if ($today > $target_date) {
        $target_date->modify('+1 year');
    }

    // Calculate the difference in days
    $interval = $today->diff($target_date);
    $days_left = $interval->days;

    // Return the appropriate response
    if ($days_left === 0) {
        return $today_message;
    } elseif ($days_left === 1) {
        return $tomorrow_message;
    } else {
        return str_replace("X", $days_left, $countdown_message);
    }
}

WordPress Shortcode

If you want to utilize this in WordPress, add the above code and the code below into a custom plugin. Plugins are advantageous over using your theme or child theme functions because you can still update your theme, and the content will continue to function correctly.

// WordPress shortcode to use the countdown function
function countdown_shortcode($atts) {
    // Extract attributes with default values for Christmas (December 25)
    $atts = shortcode_atts(
        [
            'month' => 12,
            'day' => 25,
            'today_message' => 'Today is the big day!',
            'tomorrow_message' => "It's happening tomorrow!",
            'countdown_message' => "Only X days left!",
        ],
        $atts
    );

    // Ensure month and day are integers
    $month = intval($atts['month']);
    $day = intval($atts['day']);
    $today_message = sanitize_text_field($atts['today_message']);
    $tomorrow_message = sanitize_text_field($atts['tomorrow_message']);
    $countdown_message = sanitize_text_field($atts['countdown_message']);

    // Call the countdown function and return the result
    return countdown_to_day($month, $day, $today_message, $tomorrow_message, $countdown_message);
}

// Register the shortcode with WordPress
add_shortcode('countdown', 'countdown_shortcode');

Explanation for the Shortcode

The countdown_shortcode function integrates the countdown_to_day functionality into WordPress using a shortcode. This allows content creators to easily include countdowns in posts or pages.

Attributes:

1. month: Specifies the target month (default is 12 for December).
2. day: Specifies the target day (default is 25 for Christmas).
3. today_message: Custom message for when the target date is today (e.g., “Happy Birthday!”).
4. tomorrow_message: Custom message for when the target date is tomorrow (e.g., “It’s Christmas Eve!”).
5. countdown_message: Customizable countdown message with X replaced by the number of days left (e.g., “Only X days until the event!”).

How to Use: In a WordPress post or page, use the shortcode like this:

[countdown month="12" day="25" today_message="Merry Christmas!" tomorrow_message="It's Christmas Eve!" countdown_message="Only X days until Christmas!"]

Output Examples:

• On December 25: “Merry Christmas!”
• On December 24: “It’s Christmas Eve!”
• On December 20: “Only 5 days until Christmas!”

Here’s the output:

Only 244 more days until Christmas!

This shortcode makes providing dynamic, personalized event reminders in WordPress content easy. It supports full customization for various occasions and is a valuable tool for engaging users.