jquery.ajaxSubmit.js - Effortlessly submit forms using AJAX and JSON

Developed by Cory LaViska for A Beautiful Site, LLC

Licensed under the MIT license: http://opensource.org/licenses/MIT

Overview:

This plugin provides a minimal, lightweight solution to submit forms using AJAX and JSON. There is no client side validation included, as that is outside the scope of this plugin. All validation is expected to happen on the server.

Features:

• Makes regular HTML forms AJAX-capable.
• Minimal markup.
• Handles form serialization so you don't have to.
• Shows/hides a loader and message if you provide them.
• Highlights invalid fields.
• Callbacks for success, error, before, and after.
• API to disable/enable form inputs.
• API to reset the form (including loader, message, and invalid fields)
• Compact! (about 240 lines)

Installing

Include the minified version of this plugin in your project or install via NPM:

npm install --save @claviska/jquery-ajaxSubmit

Form syntax

Create a form as you normally would in HTML. By default, the action and method attributes will be used as the target URL and method for the AJAX request. Alternatively, you can specify them as options (see below for details).

You can optionally add a loader container anywhere inside the form that will be shown/hidden automatically when the form is submitted:

<div class="form-loader">
  <img src="loader.gif">
</div>

You can optionally add a message container anywhere inside the form that will be shown/hidden and populated automatically when the form receives a message from the server:

<div class="form-message"></div>

Attaching the plugin

Minimal example that logs the server's response if successful:

Minimal example with success callback:

$('form').ajaxSubmit({
  success: function(res) {
    console.log(res);
  }
});

Example with all possible options and callbacks:

$('form').ajaxSubmit({
    // Options (default values shown)
    data: function() {
      return $(this).serialize();
    },
    hideInvalid: function(input) {
      $(input).closest('.form-group').removeClass('has-warning');
    },
    loader: '.form-loader',
    message: '.form-message',
    messageErrorClasses: 'message-error',
    messageSuccessClasses: 'message-success',
    method: function() {
      return $(this).attr('method');
    },
    showInvalid: function(input) {
      $(input).closest('.form-group').addClass('has-warning');
    },
    url: function() {
      return $(this).attr('action');
    },

    // Callbacks
    after: function(res) { ... },
    before: function() { ... },
    error: function(res) { ... },
    success: function(res) { ... }
});

Options

• data: The data to send to the server. This option can also be a function that returns data. By default, it uses the form's serialized data.

• hideInvalid: A function to be called on all invalid inputs to effectively undo the changes made by the showInvalid function.

• loader: A selector that points to the form's loader. This will be shown/hidden automatically using the HTML hidden property. Defaults to .form-loader.

• message: A selector that points to the form's message container. This will be shown/hidden automatically using the HTML hidden property. Defaults to .form-message.

• messageErrorClasses: One or more space-separated classes to attach to the message container when the response is erroneous. Defaults to message-error.

• messageSuccessClasses: One or more space-separated classes to attach to the message container when the response is successful. Defaults to message-success.

• method: The method to use (i.e. GET or POST). This option can also be a function that returns the method. By default, it uses the form's method attribute.

• showInvalid: A function to be called on all invalid inputs as returned by res.invalid. Use it to apply error styles, etc. The default behavior is compatible with Bootstrap 4 and will highlight the closest .form-group using the .has-warning class.

• url: The URL to send the request to. This option can also be a function that returns the URL. By default, it uses the form's action attribute.

You may also update the default options before instantiation:

$.ajaxSubmit.defaults.optionName = yourValue;

Callbacks

All callbacks are called in the context of the respective form (i.e. refer to the form using this inside your callbacks).

The success and after callbacks return the server's JSON response as their first argument.

• after(res): runs after the request has completed and your server returns a response.
• before(): runs before the request is sent. Returning false will cancel submission.
• error(res, err): runs when your server returns an unsuccessful response (e.g. 400 BAD REQUEST).
• success(res): runs when your server returns a successful response (e.g. 200 OK).

Methods

Methods are called using this syntax:

$('form').ajaxSubmit('method', arg);

The following API methods are supported:

• busy: sets the form's busy state. Pass in true or false.

• create (default): initializes the plugin.

• destroy: returns the form to its pre-initialized state.

• disable: disables/enables all inputs. Pass in true or false.

• reset: resets the form to its original state, including input values, loaders, and messages.

Responding from the server

Your server should return a well-formed JSON response with an appropriate HTTP status code. The response can contain any data you want, but there are a couple reserved properties:

{
  "invalid": ["username", "password"],
  "message": "Invalid username or password"
}

• invalid: Optional. An array of field names to be marked erroneous by the plugin.

• message: Optional. A string of plain text that will be injected into the message container.

Responding with PHP

In PHP, you can return a JSON response like this:

<?php
http_response_code(400); // Bad Request
header('Content-Type: application/json'); // Send as JSON
exit(json_encode([
  'invalid': ['username', 'password'],
  'message': 'Invalid username or password'
]));