here in April month there is not 31 date even though this code show me output if I enter date like which is not in month like 31 is not in june as well and if i enter date 29 in non leap year february then i want other msg like date is not valid and all these things i need in this program only in java script part. I am saying again I want this validation in this app please give me right solution I am mailing this question since last two days

Countdown To... Event Name: Event Date: Ddd happened 274 day(s) ago. (Sun May 01 2022) (c) "YourName/Student Number Here" 2022