symfony2中的复选框验证

I am creating a registration form in symfony2. I need to validate this checkbox, If a user has not checked this checkbox then there should be a client side validation.I have used client side validation also but it is not validating it.
This is my registration form type.

$builder->add('check', 'checkbox', array(
                    'label'     => 'I agree the terms and conditions',
                    'required'  => false,
                    'mapped' => false,
                    'value'=>false,
                    'translation_domain' => 'FOSUserBundle'));

This is my client side Java script

var check = $("#fos_user_registration_form_check").val();
                    if(check!=1)
                    {
                        $("#msgCheck").html('Check the Box').css('color','red').show();
                        $error=true;
                    }else{
                        $("#msgCheck").hide();
                        $error=false;
                    }

Can you test with

if($("#fos_user_registration_form_check").is(':checked'))
{
    $("#msgCheck").html('Check the Box').css('color','red').show();
    $error=true;
} else {
    $("#msgCheck").hide();
    $error=false;
}

I had many client validations to be done on this form so what I did is that, I declared error as false in the starting and then did all the validations in the similar way. otherwise error was going true for many situations so this is a better solution.

  $error=false;
       if($("#fos_user_registration_form_check").is(':checked'))
        {
            $("#msgCheck").html('Check the Box').css('color','red').show();
            $error=true;
        } else {
            $("#msgCheck").hide();

        }