防止Ajax调用中的JavaScript中的默认行为或标记单击事件 [英] Prevent Default Behavior or A Tag Click Event in JavaScript Inside Ajax Call

问题描述

我过去曾经使用 e.preventDefault（）来取消点击事件，但是我很难弄清楚为什么它在这种情况下不起作用。我在具有类名的列中分配了所有标签，然后使用 document.queryselectorAll（.classname）获取对它们的引用，然后为每个标签添加一个click事件，来自服务器的值，如果不满足验证条件，则应阻止默认值并提供用户消息。

I have used e.preventDefault() in the past to cancel a click event, but I am having trouble figuring out why it isnt working in this scenario. I assigned all a tags in a column with a classname, then get references to them with document.queryselectorAll(.classname), then for each a tag add a click event that gets values from server, and if validation not met should prevent default and give user message.

(function(){
const userName = document.getElementById('FullName').value;

// route
$route = '';
if (CheckDeploy(window.location.origin)) {
    $route = '/x/GetReviewerCheck/';
} else {
    $route = '/servername/s/GetReviewerCheck/';
}

let ReviewButtons = document.querySelectorAll('.verifyReviewer'); // .verifyReviewer = className of all a tags in table column

for (var i = 0; i < ReviewButtons.length; i++) {
    const ReviewButton = ReviewButtons[i];
    ReviewButton.addEventListener('click', function (e) {
        let newRow = ReviewButton.parentElement.parentElement;
        let AuditorName = newRow.cells[2].innerText;
        let ReviewType = newRow.cells[8].innerText;

        let ReviewTypeID = 0;
        if (ReviewType == 'Peer Review') {
            ReviewTypeID = 3;
        } else if (ReviewType == 'Team Leader Review') {
            ReviewTypeID = 4;
        }
        else if (ReviewType == 'Supervisor Review') {
            ReviewTypeID = 5;
        }

        let id = newRow.cells[0].firstChild.getAttribute('id').split('_')[1];

        $.ajax({
            url: $route,
            type: 'POST',
            data: { userName: userName, auditor: AuditorName, reviewType: ReviewTypeID, recordID: id },
            success: function (data) {
                // if data is 1, prevent default
                if(data == 1){
                    e.preventDefault();
                    return false;
                }
            }
        });

    }, false);
}
})();

推荐答案

它不起作用，因为响应是异步的。仅在ajax调用获得服务器的响应后，才会执行e.preventDefault（）。
您可以执行此操作。

It's not working because, the response is asynchronous. e.preventDefault() will be executed only after ajax call gets a response from the server. You can do this.

1. 阻止所有操作的默认操作。


2. 等待


3. 如果响应不是1，则取消绑定preventDefault（）。

I更新了for循环，并注释了更改。

I have updated the for loop, and commented the changes. Kindly do check.

for (var i = 0; i < ReviewButtons.length; i++) {
        const ReviewButton = ReviewButtons[i];
        ReviewButton.addEventListener('click', function (e) {
            let newRow = ReviewButton.parentElement.parentElement;
            let AuditorName = newRow.cells[2].innerText;
            let ReviewType = newRow.cells[8].innerText;

            let ReviewTypeID = 0;
            if (ReviewType == 'Peer Review') {
                ReviewTypeID = 3;
            } else if (ReviewType == 'Team Leader Review') {
                ReviewTypeID = 4;
            }
            else if (ReviewType == 'Supervisor Review') {
                ReviewTypeID = 5;
            }

            let id = newRow.cells[0].firstChild.getAttribute('id').split('_')[1];

            $.ajax({
                url: $route,
                type: 'POST',
                data: { userName: userName, auditor: AuditorName, reviewType: ReviewTypeID, recordID: id },
                beforeSend:function()
                {
                    e.preventDefault(); //Prevent default action for all instances.
                },
                success: function (data) {
                    // if data is 1, prevent default
                    if(data != 1){
                        $(this).unbind('click'); // Restores the click default behaviour if data != 1
                        return false;
                    }

                }
            });

        }, false);
    }

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