如何禁用小于或等于动态字段的开始日期选取器的结束日期

Question

此处仅对于默认值，将禁用小于开始日期的结束日期。我如何为动态字段完成它？

var constants = {
MAX_YEAR: "2020"
};
var datePickerOptions = {
maxDate: constants.MAX_YEAR + '-12-31',
changeYear: true,
changeMonth: true,
dateFormat: 'yy-mm-dd',
onSelect: function(selected) {
$("#enddate").datepicker("option", "minDate", selected)
}
};
$(document).ready(function() {
$('.datepicker').datepicker(datePickerOptions);
$('#container').on('click', '.remove', function() {
$(this).parent().remove();
});
$('#add').on('click', function() {
var row = $('div.addNew:first').clone();
$('#container').append(row);
var pickers = row.find(".datepicker");
pickers.removeAttr("id");
pickers.removeClass("hasDatepicker");
pickers.datepicker(datePickerOptions);
});
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.css" />
<div id="container">
<div class="addNew" ?>
Start Date :
<input name='settings[start_date][]' , value="2018-06-25" class="datepicker year-date-month-calendar input-small removetradingdates-block" id="startdate" /> End Date :
<input name='settings[end_date][]' , value="2018-06-25" class="datepicker year-date-month-calendar input-small removetradingdates-block" id="enddate" />
<input type="button" class="remove" value="Remove" />
</div>
<input type="button" id="add" value="Add Periods" />
</div>

Answer 1

<div id="container">
<div class="addNew" ?>
Start Date :
<input name='settings[start_date][]', value="2018-06-25"
class="datepicker year-date-month-calendar input-small removetradingdates-block startdate" />
End Date :
<input name='settings[end_date][]', value="2018-06-25"
class="datepicker year-date-month-calendar input-small removetradingdates-block enddate" />
<input type="button" class="remove" value="Remove" />
</div>
<input type="button" id="add" value="Add Periods" />
</div>
var constants = {
MAX_YEAR: "2020"
};
var datePickerOptions = {
maxDate: constants.MAX_YEAR + '-12-31',
changeYear: true,
changeMonth: true,
dateFormat: 'yy-mm-dd',
onSelect: function(selected) {
$(this).parent().find(".enddate").datepicker("option","minDate", selected)
$(this).parent().find(".startdate").datepicker("option","maxDate", selected)                   
}
};
$(document).ready(function() {
$('.datepicker').datepicker(datePickerOptions);
$('#container').on('click', '.remove', function() {
$(this).parent().remove();
});
$('#add').on('click', function() {
var row = $('div.addNew:first').clone();
$('#container').append(row);
var pickers = row.find(".datepicker");
pickers.removeAttr("id");
pickers.removeClass("hasDatepicker");
pickers.datepicker(datePickerOptions);
});
});