Key UX concepts

When there are unsaved changes on the page, and users attempt to navigate away or initiate any action that will discard unsaved data, launch a modal for users to confirm or cancel the action. There are several key concepts regarding the goal and behavior of the confirmation modals.

Data loss prevention

Preventing data loss is critical to keeping the customer's trust in a product. Data loss can be a severe consequence of either unconscious errors, such as accidental clicks, or mistakes due to incomplete information of the service. For common input tasks, having the friction ensures that users know the implications of their actions. When the amount of data entered by users is large and the changes could be difficult to reproduce in case of loss, consider saving their progress at intervals. This helps to guard against loss from a non-responsive browser or other types of system breakdowns.

Confirm only when necessary

A confirmation modal prevents data loss when unsaved changes exist on the page. However, it’s not necessary if a user hasn’t made any changes on the page, because there is no potential data loss. Adding friction to the user's actions when it's unnecessary can lead to frustration.

Consistency over exception

The behavior of the confirmation modal should be consistent across services so that users don't need to guess whether friction will appear or not. The confirmation modal should be launched irrespective of the size or severity of changes on the page or what the user's actions are.

Confirmation modals

In-page modal

Show an in-page modal when users trigger the buttons and links on the page to perform actions that will result in data loss. For example, a user has made changes on a form and attempts to exit the form by:

  • Selecting the Cancel button on a form.

  • Selecting a link in the side navigation.

  • Selecting a breadcrumb item.


  • Modal

    • Follow the guidelines for modal.

  • Alert

    • Use a warning alert to warn users of the potential data loss.

Browser-native modal

When a user takes a browser-level action that will result in data loss, such closing a browser tab, the only way to prevent data loss is to use the browser-native modal. All modern browsers support native confirmation modals that can be invoked when users navigate away from the current page. Due to browser security restrictions, the text of the modal is not customizable. Show the browser-native confirmation modal when users use any browser functions that will result in data loss, including:

  • Closing the browser tab.

  • Reloading the browser tab.

  • Quitting the browser application.

  • Navigating to another page from browser history.

  • Modifying the URL in the browser address bar.

unsaved changesunsaved changes

Example: Chrome browser-native modal, launched when the user leaves the page.

General guidelines


  • Launch a confirmation modal after any action that could result in data loss, regardless of the size or type of data.


  • Don't launch a confirmation modal when users use controls tied to progressive disclosure.
  • Don't launch a confirmation modal when there is no risk of data loss. For example, when no change has been made on the page, all changes have already been saved to the database, or the action will open another tab.
  • Don’t implement an option on the in-page confirmation modal for users to skip it in the future, because users won’t have a mechanism to re-activate the modal.

Writing guidelines

General writing guidelines

  • Keep labels and descriptions clear and concise.

  • Use parallel sentence structure.

  • Use sentence case for all text. Don’t use title case.

  • Use terminal punctuation (periods, exclamation points, question marks).

  • Use present-tense verbs and active voice wherever possible.

  • Don't use "please," "thank you," or Latinisms such as "e.g.," "i.e.," or "etc."


  • Explain to users that the unsaved changes on the page will be discarded if users proceed with the action.

  • Use the following text as the default message:

    • Are you sure that you want to leave the current page? The changes that you made won't be saved.

  • When there are any non-obvious risks involved in the user's actions such as irreversible changes, or the actions have high risks such as causing financial loss for users, include additional messaging explaining these risks.

  • Follow the writing guidelines for alert.


  • For the modal header, use this text: Leave page

  • For the primary action button of the modal, use this text: Leave

  • Follow the writing guidelines for modal.

Accessibility guidelines

Follow the accessibility guidelines for modal and alert.


The browser-native modal is launched by the the beforeunload event. For more information about the event, see the documentation for the beforeunload event  on MDN web docs. In order to display the in-page modal, you need to intercept any actions that would discard unsaved changes. The following code shows an example implementation.

import React from 'react';
import { Alert, AppLayout, Box, Button, Form, Modal, SideNavigation, SpaceBetween } from '@cloudscape-design/components';

export default class App extends React.Component {
  constructor(props) {
    this.state = {
      hasChanges: false,
      showModal: false,

    this.onBeforeUnload = this.onBeforeUnload.bind(this);
    this.onNavigate = this.onNavigate.bind(this);

  componentDidMount() {
    window.addEventListener('beforeunload', this.onBeforeUnload);

  componentWillUnmount() {
    window.removeEventListener('beforeunload', this.onBeforeUnload);

  onBeforeUnload(evt) {
    if (this.state.hasChanges) {
      // Cancel the event as stated by the standard.
      // Chrome requires returnValue to be set.
      evt.returnValue = '';

  onNavigate(evt) {
    // keep the locked href for our demo pages

    if (this.state.hasChanges) {
      this.setState({ modalVisible: true });

  render() {
    return (
            <Form>&lt;-- Form elements go here --&gt;</Form>

              onDismiss={() => this.setState({ showModal: false })}
              header="Leave page"
                <Box float="right">
                  <SpaceBetween direction="horizontal" size="xs">
                    <Button variant="link" onClick={() => this.setState({ showModal: false })}>
                    <Button variant="primary">Leave</Button>
              <Alert type="warning">
                Are you sure that you want to leave the current page? The changes that you made won't be saved.
        navigation={<SideNavigation activeHref="#/distributions" onFollow={this.onNavigate} />}

Related patterns and components

With the create new resource pattern, users can create new resources.
Use the edit resource flow when you want a user to manage a service resource by editing its properties and configuration, and then saving the changes.
A brief message that provides information or instructs users to take a specific action.
A user interface element subordinate to an application's main window. It prevents interaction with the main page content, but keeps it visible with the modal as a child window in front of it.