Wait until all jQuery Ajax requests are done?

Question

How do I make a function wait until all jQuery Ajax requests are done inside another function?

In short, I need to wait for all Ajax requests to be done before I exe

Answer 1

As other answers mentioned you can use ajaxStop() to wait until all ajax request are completed.

$(document).ajaxStop(function() {
     // This function will be triggered every time any ajax request is requested and completed
});

If you want do it for an specific ajax() request the best you can do is use complete() method inside the certain ajax request:

$.ajax({
    type: "POST",
    url: "someUrl",
    success: function(data) {
        // This function will be triggered when ajax returns a 200 status code (success)
    },
    complete: function() {
        // This function will be triggered always, when ajax request is completed, even it fails/returns other status code
    },
    error: function() {
        // This will be triggered when ajax request fail.
    }
});

But, If you need to wait only for a few and certain ajax request to be done? Use the wonderful javascript promises to wait until the these ajax you want to wait are done. I made a shortly, easy and readable example to show you how does promises works with ajax.
Please take a look to the next example. I used setTimeout to clarify the example.

// Note:
// resolve() is used to mark the promise as resolved
// reject() is used to mark the promise as rejected

$(document).ready(function() {
    $("button").on("click", function() {

        var ajax1 = new Promise((resolve, reject) => {
            $.ajax({
                type: "GET",
                url: "https://miro.medium.com/max/1200/0*UEtwA2ask7vQYW06.png",
                xhrFields: { responseType: 'blob'},
                success: function(data) {
                    setTimeout(function() {
                        $('#image1').attr("src", window.URL.createObjectURL(data));
                        resolve(" Promise ajax1 resolved");
                    }, 1000);
                },
                error: function() {
                    reject(" Promise ajax1 rejected");
                },
            });
        });

        var ajax2 = new Promise((resolve, reject) => {
            $.ajax({
                type: "GET",
                url: "https://cdn1.iconfinder.com/data/icons/social-media-vol-1-1/24/_github-512.png",
                xhrFields: { responseType: 'blob' },
                success: function(data) {
                    setTimeout(function() {
                         $('#image2').attr("src", window.URL.createObjectURL(data));
                         resolve(" Promise ajax2 resolved");
                    }, 1500);
                },
                error: function() {
                    reject(" Promise ajax2 rejected");
                },
            });
        });

        var ajax3 = new Promise((resolve, reject) => {
            $.ajax({
                type: "GET",
                url: "https://miro.medium.com/max/632/1*LUfpOf7teWvPdIPTBmYciA.png",
                xhrFields: { responseType: 'blob' },
                success: function(data) {
                    setTimeout(function() {
                         $('#image3').attr("src", window.URL.createObjectURL(data));
                         resolve(" Promise ajax3 resolved");
                    }, 2000);
                },
                error: function() {
                    reject(" Promise ajax3 rejected");
                },
            });
        });
        
        Promise.all([ajax1, ajax2, ajax3]).then(values => {
            console.log("We waited until ajax ended: " + values);
            console.log("My few ajax ended, lets do some things!!")
        }, reason => {
            console.log("Promises failed: " + reason);
        });
        
        // Or if you want wait for them individually do it like this
        // ajax1.then(values => {
        //    console.log("Promise 1 resolved: " + values)
        // }, reason => {
        //     console.log("Promise 1 failed: " + reason)
        // });
    });

});

img {
  max-width: 200px;
  max-height: 100px;
}

Make AJAX request