Disable symfony 2 csrf token protection on ajax submit

If you're looking for a bit easier and faster solution than suggested in answer above, here's how:

<?php

// ...

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;
use Symfony\Component\OptionsResolver\OptionsResolver;

class MyType extends AbstractType
{
    // ...

   public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'csrf_protection' => false,
        ));
    }
}

.. or if you're using older versions (Symfony 2.0.*):

<?php

// ...

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;

class MyType extends AbstractType
{
    // ....

    public function getDefaultOptions(array $options)
    {
        $options = parent::getDefaultOptions($options);
        $options['csrf_protection'] = false;

        return $options;
    }
}

Consult the Symfony documentation for additional information.

Edit: updated answer to latest Symfony version, thanks naitsirch

Using the form factory

For those who want to create a simple form in a controller:

$form = $this->container->get('form.factory')
    ->createNamedBuilder(null, 'form', null, array('csrf_protection' => false))
    ->add('yourField','text', array(
        'label' => false,
        'mapped' => false
    ))
    ->getForm();

public function configureOptions(OptionsResolver $resolver)
{
    $resolver->setDefaults([
        'csrf_protection' => false,
    ]);
}