自定义列表比较Sharepoint中的日期

I am creating two columns Start and end date, when the user enters end date I should validate it with the start date to check that its greater than start date, is there a way to do that?? I am using Custom Library for this, My requirement is I have to store a document with start and end date and I need to do some validations on it.I am creating two columns Start and end date, w