function bf(n){
    var contents = document.getElementById("rb" + n);
    var textarea = document.createElement('textarea');
    if(contents.hasChildNodes()){
        document.getElementById("rb_text" + n).innerHTML = "";
        contents.removeChild(contents.firstChild);
        document.getElementById("rs" + n).disabled = false;
        return;
    }
    document.getElementById("rb_text" + n).innerHTML = "<font size=\"-1\">コメントを入力してください。</font>";
    document.getElementById("rs" + n).disabled = true;
    textarea.id =  'res_comment_textarea';
    textarea.name = "res_comment_textarea";
    textarea.style.width = "500px";
    textarea.style.height = "100px";
    textarea.value = document.getElementById("rs" + n).value;
    contents.appendChild(textarea);
}