$(document).ready(function(){
    $(".news-comments .add-comment-form .new_comment_btn").click(function(){
        var form = $(this).parent().parent();
        var text = form.children().children("textarea").val();
        if (text.length > 0) { form.children(".error").hide(); form.submit(); }
        else { form.children(".error").show(); }
    });
});