$(function(){
    $('.comment_form').one('click', function(){
        $.ajax({
            url: '/_comments/capcha/',
            dataType: 'json',
            data: {
                object_id: $('#object_id').val(),
                object_type: $('#object_type').val(),
                secret_key: $('#secret_key').attr('pre_value')
            },
            success: function(data){
                $('#secret_key').val(data.secret_key);
            }
        });
    });
});