How to calculate date difference using jquery?

Question

Hi,

 

I have one requirement and in that I want to calculate date difference using jQuery.

 

In this one date is modified date of ShaPoint lsit and second is todays date.

 

So I want difference between todays date and modified date.

 

I tried 2-3 ways but it is showing below errors

 

1) Invalid date format

2) NAN

 

Please help