In this tutorial, I will tell you about how to create past date Validation In SharePoint 2013.
Keep the field text id ready from the input code line in order to map it to the required past date selection validation ie. Selected Date <= TodaySharePoint-2013-Hosting1

Create a JQ function representing link to that field’s id “txt_dateofintimation” for selecting only past dates and the max date is today only with a gap of 3 months.

Go to that site’s page and start filling in  the details.

Here is the validation pop up for Date field to be selected.

As shown below in the bottom bar and the function also allows us to select the dates before today as per the validation requirement.