form-extra-events

Add extra events for submit html forms.

Russian readme

Install

npm install form-extra-events

Usage

This example implements adding the loading class for all forms during submission.

import 'form-extra-events';

document.addEventListener('submitstart', function(e) {
    e.target.classList.add('loading');
});
document.addEventListener('submitend', function(e) {
    e.target.classList.remove('loading');
});

Documentation

Events

form-extra-events adds the following events for all forms:

• submitlast - triggered after executing all handlers of the standard submit event, here you can still cancel the standard browser behavior by calling preventDefault(), but this is recommended only to send a request in other ways, for example, via AJAX, that is, the request must be executed in any case;
• submitbefore - triggers before the form is submitted, here you can still modify the form, but you cannot cancel the standard browser behavior by calling preventDefault(), i.e. the event is guaranteed to be executed before being sent;
• submitstart - triggered after the form has been submitted, changes in the form will not change the request;
• submitend - triggered after the form has been submitted.

Warning: the submitend event is based on the unload event, with all its limitations. For example, you cannot open a window by calling window.open(). Also for many mobile browsers this event is not triggered.

Event params

The event object contains additional parameters:

• transport {string} - for events submitbefore, submitstart, submitend passes the name of the transport with which the form is transmitted. More details below in the section transports.
• activeButton {Element} - for the events submitlast, submitbefore passes the button element with which the form was sent.

Transports

The submitlast event is introduced specifically for the implementation of various transports. In form-plus, this event is used to submit form via AJAX. This AJAX transport also generates the events submitbefore, submitstart, submitend, but with a different parameter of the event transport. If you need to capture the event of a regular browser-based form submission, you need to check the transport === 'default' parameter in the handler:

document.addEventListener('submitbefore', function(e) {
    if (e.detail.transport === 'default') {
        let hidden = document.createElement('input');
        hidden.name  = 'isNoAjax';
        hidden.value = '1'; 
        e.target.appendChild(hidden);
    }
});

Detect download state

By default, the script cannot catch the end of form submission, if the browser has switched to the file download state, so in this case it does not handle the submitend event. Similarly, if you specify the attribute target="_blank" for the form. To catch the submitend event in such cases, use the catch-download script from the form-plus package.

Import types

There are several entry points for importing a library:

• import ExtraEvents from 'form-extra-events' - similarly register-with-shims;
• import ExtraEvents from 'form-extra-events/standard' - easy import without polyfills for ie11, register is required;
• import ExtraEvents from 'form-extra-events/with-shims' - import with shims for ie11, register is required;
• import ExtraEvents from 'form-extra-events/with-polyfills' - import with polyfill for ie11, register is required;
• import ExtraEvents from 'form-extra-events/register' - import without polyfills for ie11, auto-register;
• import ExtraEvents from 'form-extra-events/register-with-shims' - import with shims for ie11, auto-register;
• import ExtraEvents from 'form-extra-events/register-with-polifills' - import with polyfill for ie11, auto-register.

Differences shims from polyfills you can read in polyshim package.

When directly include the script from the dist folder to the browser, you can get an ExtraEvent instance via window.FormExtraEvents.default.

Registration and name of events

When importing a package without register, you need to register it. When registering, you can replace the event names:

import ExtraEvents from 'form-extra-events/with-shims';

ExtraEvents.register({
    eventLast: 'last',
})

Methods

• register([settings]) - register library
  • settings {Object} [{}] - settings
  • @return {Object} - returns the current settings
• unregister() - unregister library
• getSettings() - returns the current settings
  • @return {Object}
• getSendingForm() - returns the current form being submitted
  • @return {HTMLFormElement|null}
• setShim([setClosest[, setObjectAssign[, setCustomEvent]]]) - sets shims for non-cross-browser methods
  • setClosest {Function|null} - shim for Element.prototype.closest
  • setObjectAssign {Function|null} - shim for Object.assign
  • setCustomEvent {Function|null} - shim for new CustomEvent

Settings

• eventLast {string} ['submitlast'] - name of event submitlast
• eventBefore {string} ['submitbefore'] - name of event submitbefore
• eventStart {string} ['submitstart'] - name of event submitstart
• eventEnd {string} ['submitend'] - name of event submitend

Testing

For tests, you need to install selenium-drivers for browsers. To run tests, use:

npm test

Browsers support

• Internet Explorer 11+
• Other modern browsers

For old browsers use version 1.x.