@DhanasekarC0202 Thanks Dhanasekar for your reply! Yes, that is an option. The only issue is that post value would occur only after all content is typed in and the user tabs out of the text area. But yeah, I will have to modify my use case a bit.
Triggering post value on change actually cannot be used for our use case.
The reason for the post value is actually to display remaining count of characters that can be entered in the text area. When user tabs out of the field, we will not show the remaining character count.
Also, we cannot use the OOTB feature of showing remaining characters since the total character count is not a static value.