Restrict Past Date in Sharepoint Date Field

I have a Sharepoint List with a date column.  When the user fills the data in NewForm.aspx and after click the OK button i need to verify the date column and restrict the user to enter Valid date. I thought of writing event Handler. But Properties.CustomError in event Handler will take the user to the Error page. I need to restrict the user to stay in the same page. i..e NewForm.aspx.

Note: I don't need to use SHarepoint Designer or Jquery

Any solution in Event Handler to stay in that page. Please anybody help me...