count的值永远是0。是因为filter是异步处理的原因吗？

function calcCount(tAry) { var count = 0 var newAry = taskAry.filter(item => item.isVaild == false) count = newAry.length $('#num_td').text(count + 'item left') } function updataTask() { var html = template('taskTpl', { tasks: taskAry }) $('.tdthins').html(html) } var taskAry = [] $.ajax({ type: 'get', url: '/get-task', data: {}, success: function (data) { taskAry = JSON.parse(data) updataTask() calcCount() }

解决问题，而不是换种写法

async function ajax(url) {
    return new Promise(function (resolve, reject) {
        let ajaxSetting = {
            url: url,
            success: function (response) {
                resolve(response);
            },
            error: function () {
                reject("请求失败");
            }
        }
        $.ajax(ajaxSetting);
 
    });
}
 
async function run() {
    let response1 = await ajax("data1.json");
    let response2 = await ajax(response1["url"]);
    let response3 = await ajax(response2["url"]);
    console.log(response3);
}
 
//不阻塞
run();

参考

你加个延时看看，把newAry的值console.log

你检查下taskAry拿到数据了吗，拿到之后看下newAry这个结果，调试下即可

用await 和async字段