start_date and end_date

I am trying to validate start_date and end_date to show alert start date should be lesser than end date.
But i dint able to validate.
When i used date.parse and i have checked for different testcases.
TC.1: 22/08/2016 - 22/08/2016
TC.2:22/08/2016 - 24/08/2016
TC.3:22/08/2016 - 20/08/2016.
By checking these testcases, i have come to know that startdate is always showing greater value then enddate.
please help me to solve dis problem