Countdown Timer using ACF in Oxygen

This members-only tutorial provides the steps to set up a countdown timer in Oxygen with the value coming from a Date Time Picker type of custom field on an Options page instead of hardcoding the value (like "Nov 23, 2028 00:00:00").

Update: Changes for a calendar-styled countdown are provided at the end.

Step 1

Install and activate ACF Pro and Code Snippets plugins.

Step 2

Let us enable an ACF Options page.

Go to Snippets > Add New.

Title: Enable ACF Options Page

Code:

if ( function_exists( 'acf_add_options_page' ) ) {
    acf_add_options_page();
}

Set the snippet to run only in the admin area.

Step 3

Go to Custom Fields > Add New.

Create a field group titled say, "Sitewide" having a Date Time Picker-type of custom field with the name of countdown_date. Set it to appear on the Options Page.

Set Display Format and Return Format to F j, Y H:i:s.

Step 4

Click Options in the WP admin and pick your desired countdown date.

Step 5

Install and activate My Custom Functionality plugin.

Connect to your hosting account using a FTP client and navigate to site's /wp-content/plugins/my-custom-functionality-master.

Create a file named say, countdown-date.js in the plugin's assets/js directory having the following code: