Magento 2, how to add 'textbox' into 'cancel modal'?

Question

Using magento 2.2, admin. I need to add textbox into dialog when confirm Cancel status in sale order.

Answer 1

create module for override js file
\app\code\Magento\custombackend\etc\module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Magento_custombackend" setup_version="0.0.1">
        <sequence>
            <module name="Magento_Sales"/>
        </sequence>
    </module>
</config>

\app\code\Magento\custombackend\view\adminhtml\requirejs-config.js

var config = {
    map: {
        '*': {
            'Magento_Sales/order/view/post-wrapper': 'Magento_custombackend/js/order/view/post-wrapper'
        }
    }
};

\app\code\Magento\custombackend\view\adminhtml\web\js\order\view\post-wrapper.js

/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

define([
    'jquery',
    'Magento_Ui/js/modal/confirm',
    'mage/translate'
], function ($, confirm) {
    'use strict';

    /**
     * @param {String} url
     * @returns {Object}
     */
    function getForm(url) {
        return $('<form>', {
            'action': url,
            'method': 'POST'
        }).append($('<input>', {
            'name': 'form_key',
            'value': window.FORM_KEY,
            'type': 'hidden'
        }));
    }

    $('#order-view-cancel-button').click(function () {
        var msg = $.mage.__('Are you sure you want to cancel this order? <input type="text">'),
            url = $('#order-view-cancel-button').data('url');
        confirm({
            'content': msg,
            'actions': {

                /**
                 * 'Confirm' action handler.
                 */
                confirm: function () {
                    getForm(url).appendTo('body').submit();
                }
            }
        });

        return false;
    });

    $('#order-view-hold-button').click(function () {
        var url = $('#order-view-hold-button').data('url');

        getForm(url).appendTo('body').submit();
    });

    $('#order-view-unhold-button').click(function () {
        var url = $('#order-view-unhold-button').data('url');

        getForm(url).appendTo('body').submit();
    });
});

\app\code\Magento\custombackend\registration.php

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
\Magento\Framework\Component\ComponentRegistrar::MODULE,    
'Magento_custombackend',    __DIR__);
?>

In magento 2.2.5 this dialog text come from this path \vendor\magento\module-sales\view\adminhtml\web\order\view\post-wrapper.js

line : 29

var msg = $.mage.__('Are you sure you want to cancel this order? <input type="text">')

add textbox like this