Magento 2: How to send data using Ajax form in custom form?

Question

Can anyone explain me how I can create a simple form on Magento-2 page to send data using Ajax? I already have a form and controller action, that send data without using ajax.

Answer 1

You can just set below code in your phtml file to use ajax, You have to change your customurl in below code,

<script type="text/javascript">
    require(["jquery"],function($) {
        $(document).ready(function() {
            var customurl = "<?php echo $this->getUrl().'frontname/index/index'?>";
            $.ajax({
                url: customurl,
                type: 'POST',
                dataType: 'json',
                data: {
                    customdata1: 'test1',
                    customdata2: 'test2',
                },
            complete: function(response) {             
                country = response.responseJSON.default_country;
                state = response.responseJSON.state;         
                console.log(state+' '+country);   
                },
                error: function (xhr, status, errorThrown) {
                    console.log('Error happens. Try again.');
                }
            });
        });
    });
</script>

inside your controller file execute() method,

<?php
 use Magento\Framework\Controller\ResultFactory;
 public function execute()
    {
        $resultPage = $this->resultFactory->create(ResultFactory::TYPE_PAGE);

        $response = $this->resultFactory->create(ResultFactory::TYPE_RAW);
        $response->setHeader('Content-type', 'text/plain');
        $country = 'india';
        $state = 'gujarat';
        $response->setContents(
            $this->_jsonHelper->jsonEncode(
                [
                    'default_country' => $country,
                    'state' => $state,
                ]
            )
        );
        return $response;
    } 

Answer 2

Accepted answer is good, but i think could be useful take advantage of the js validation that magento core offers. So, try to use below js script:

<script type="text/javascript">
require([
    "jquery",
    "mage/mage"
],function($) {
    $(document).ready(function() {
        $('#form_id').mage(
            'validation',
            { 
                submitHandler: function(form) {
                    $.ajax({
                        url: "url to module/controller/action",
                        data: $('#form_id').serialize(),
                        type: 'POST',
                        dataType: 'json',
                        beforeSend: function() {
                            // show some loading icon
                        },
                        success: function(data, status, xhr) {
                            // data contains your controller response
                        },
                        error: function (xhr, status, errorThrown) {
                            console.log('Error happens. Try again.');
                            console.log(errorThrown);
                        }
                    });
                }
            }
        );
    });
});
</script>

Don't forget that controller has to return JSON response like:

$response = $this->resultFactory
    ->create(\Magento\Framework\Controller\ResultFactory::TYPE_JSON)
    ->setData([
        'status'  => "ok",
        'message' => "form submitted correctly"
    ]);

return $response;