markInvalid is not working on date field

I am creating a custome component which will have start date and end date. Looking at start date validation. I wrote a listnere on change event where I am comparing start date should be lesser than end date and if it is not mark it as invalid. But markinvalid is not working. Kindly guide me

following is the fiddle link where I have executed my test code.

I am using 4.2.0 , classic theme.

http://ift.tt/1JbocVJ

markInvalid is not working on date field