Expiry date validation

function ExpDateChk(sender, args)
{

       
var Today = new Date();

var expDate = new Date(document.getElementById("<%# txtLicenceExpiryDate.ClientID %>").value)

if (Today.setDate(Today.getDate()+6) > expDate) {

args.IsValid = false;

}

else {

args.IsValid = true;

}

}