I have a date field
field_date_subscription in each node on my website.
Can I use it to create a countdown without necessarily creating a new field
With many modules I've seen I think is the only way... or not?
Download the Field Timer module, enable it and then for the existing Date field you can now change its format in the "Manage Display" from date/time to "jQuery Countdown" format.
This module provides field formatters which display timer or countdown. Formatters can be used for Date fields or timer fields provided by this module. The start/target date on the timer field can be any date or an entity property which represent a date (for example, created date of a node). Module provides 3 field formatters: simple text and 2 formatters based on jQuery plugins County and jQuery Countdown.
You can even use it as a field in a view.
Check out this module Countdown Timer Field
Countdown timer field module allows you to create countdown timer field to count the days, hours, minutes, and seconds until a specified event. The module uses jQuery Countdown Timer to display the countdown timer in a nice graphical way.