
I have a textbox field called "Expires on" and I am using DatePicker
$("#sfExpiresOn").datepicker({
dateFormat: "yy-mm-dd",
changeMonth: true,
changeYear: true,
minDate: 0
})
Here, I need validation because use can simply add random number here like

How can i prevent user to add random number values. (I don't need HTML 5 validation.)
Thank You