如何使用CodeIgniter表单验证库验证空复选框并通过AJAX显示消息？

Question

Displaying form error message when checkbox is not checked using CodeIgniter form validation library.

Currently, form error message is displayed only when checkbox is checked.

Here is AJAX call:

$('#add_user').on('submit', function(e) {
    e.preventDefault();

    $.ajax({
        url : $(this).attr('action'),
        method : "post",
        data: $(this).serialize(),
        dataType: "json",
        success: function(result) {
            if(result.success == true) {
                alert('Success');
            } else {
                $.each(result.errors, function(key, value) {
                    var error = $('#' + key);
                    error.closest('div.form-group')
                    .find('.error').remove();
                    error.after(value);
                });
            }
        }
    });
});

And here is PHP controller:

$this->form_validation->set_rules('agreement', 'Agreement', 'callback_agreement_checkbox');

if($this->form_validation->run()) {
            $data['success'] = true;
            $this->load->view('Success');
        } else {
            foreach($this->input->post() as $key => $value) {
                $data['errors'][$key] = form_error($key);
            }
            echo json_encode($data);
        }

public function agreement_checkbox() {
        if (empty($this->input->post('agreement'))) {
            return FALSE;
        } else {
            $error = 'Please accept TOS';
            $this->form_validation->set_message('agreement_checkbox', $error);
            return TRUE;
        }
    }

When the form is submitted without checkbox checked, error message is not displayed (but it should). It's displayed only when checkbox is checked and it's wrong.

EDIT:

I've done some modifications for support of mixing different input data:

$this->form_validation->set_rules('first_name', 'First name', 'trim|required');
$this->form_validation->set_rules('last_name', 'Last name', 'trim|required');
$this->form_validation->set_rules('email', 'E-mail', 'trim|required');
$this->form_validation->set_rules('agreement', 'Agreement', 'required');

if($this->form_validation->run()) {
            $data['success'] = true;
            $this->load->view('Success');
        } else {                
            foreach($this->input->post() as $key => $value) {
                $data['errors'][$key] = form_error($key);
            }
            if (empty($this->input->post('agreement'))) {
                $data['errors']['agreement'] = form_error('agreement', '<div id="agreement_error">', '</div>');
            }           
            echo json_encode($data);
        }

Answer 1

Callback function of Codeigniter does not defined $this->input->post() . I suggest you to use required. So it will be like this.

$this->form_validation->set_rules('agreement', 'Agreement', 'required');

it will defined if the check box was checked before it submitted. then change this code too.

if($this->form_validation->run()) {
    if(! empty($this->input->post('agreement))){
          $data['success'] = "It was checked";
        }else{
          $data['error'] = validation_errors();
    }
    echo json_encode($data);
}

Your ajax:

        success: function(result) {
        if(result.success) {
            console.log(result.success);
        } else {
            console.log(result.error);
        }
    }

Let me know the result.