promise

var workAsync = function() {
    var p = new Promise(function(resolve, rej) {
        $.get("http://....", function(rs){
            resolve("dddddddd");
        })
    });
    return p;
}

workAsync().then(function(data) {
    console.log(data);
});

var p1 = Promise.resolve(3);
var p2 = Promise.resolve(999);
Promise.all([p1, p2]).then(function(values) {
    console.log(values); // [3, 999]
});

var workAsync = function(url) {
    var p = new Promise(function(resolve, rej) {
        $.get(url, function(rs){
            resolve("dddddddd");
        })
    });
    return p;
}

var tasks = [];
tasks.push(workAsync("http://1...."));
tasks.push(workAsync("http://2...."));

Promise.all(tasks).then(function(values) {
    console.log(values); // [...]
});