I'm trying to implement a click event in one of the button I added under the Magento_Checkout module specifically under payment.html view. Now I added the below code

File location: app/design/frontend/Vendor/Module/Magento_Checkout/web/template/payment.html

<form id="co-payment-form" class="form payments" novalidate="novalidate">
    <fieldset class="fieldset">              
        <button type="button" data-bind="click: goBackShipping">Back from template</button>

Now what I want is that the goBackShipping will be triggered using KnockoutJS functionality. But I'm getting this error

knockout.js:3391 Uncaught ReferenceError: Unable to process binding "click: function(){return goBackShipping }"

This goBackShipping function is added in the checkout-data.js under the folder


and here is the code I added

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

  * Checkout adapter for customer data storage
  * @api
 ], function ($, storage) {
     'use strict';

    var cacheKey = 'checkout-data',

     * @param {Object} data
    saveData = function (data) {
        storage.set(cacheKey, data);

   // This is the newly added function
    goBackShipping = function () {
        alert("Preparing to go back");

     * @return {*}
    initData = function () {

        return { ... };

Honestly I have no idea why it's giving an error like that. Am I doing something wrong? (obviously yes because it's giving an error).

I would only like to implement a button click action using knockoutjs and simple javascript alert. But I can't get pass this error.

1 Answer 1


Your method needs to add the following class:


So overwrite this and add your method here.

goBackShipping: function () {
    alert("Preparing to go back");
  • Initially this is what I did but I'm still getting the error. That is why I ended up using the checkout-data.js. But the problem is neither of the two work. May 16, 2019 at 4:23
  • @MadzQuestioning sohel's solution is perfect and it's working perfectly in mycode Please try again pasting this code and check agian May 16, 2019 at 4:56
  • @MadzQuestioning you definitely made a mistake. Did you clear pub/static? IF you working on developer mode then no need to clear pub/static. Should clear browser js cache.
    – Sohel Rana
    May 16, 2019 at 5:17

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