为此

Question

所以我在这里创建了一个ajax请求

        function postForm(url, data) {
            const xhr = new XMLHttpRequest();

            xhr.open('POST', url, true);
            xhr.send(data);

           xhr.onreadystatechange = function () {
                const DONE = 4; // readyState 4 means the request is done.
                const OK = 200; // status 200 is a successful return.
                if (xhr.readyState === DONE) {
                    if (xhr.status === OK) {
                        const requestMessage = xhr.responseText;
                        console.log(requestMessage); // 'This is the returned text.'
                        const success = requestMessage.search(1);
                        const error = requestMessage.search(0);
                        if(success !== -1) {
                            console.log("success");
                            removeClass(modal, 'is-active');
                            closeModal();
                            window.location.reload();
                        } else {
                            console.log("error");
                            const parent = findAncestor(this, 'folder');
                            const errorMessage = document.createElement('div');
                            errorMessage.className = "errorMessage";
                            errorMessage.innerHTML = requestMessage;
                            errorMessage.innerHTML = requestMessage.replace('0','');
                            parent.append(errorMessage);
                        };
                    } else if (xhr.status === INT_ERROR) {
                         console.log(xhr.responseText);
                    } else {
                        console.log('Error: ' + xhr.status); // An error occurred during the request.
                    }
                }
            };
        }

我对此部分有疑问。我希望能够概括这一点。当用户按下调用此ajax调用的按钮时，ajax会调用他们单击的内容的父级并找到祖先，并将errorMessage添加到该元素的父级。我如何概括这个ajax？

                        console.log("error");
                        const parent = findAncestor(this, 'folder');
                        const errorMessage = document.createElement('div');
                        errorMessage.className = "errorMessage";
                        errorMessage.innerHTML = requestMessage;
                        errorMessage.innerHTML =                      
                        requestMessage.replace('0','');
                        parent.append(errorMessage);