Ajax循环内的Ajax

Question

I have the code (structure):

for (var x = 0; x < array1.length; x++){
(function(x) {
    $.ajax({
    url : "http://someurl1.ru/"+array1[x]+"/",
    async: false,
    success : function(someresult1){
        array2.length = 0;
        array3.length = 0;
        var br = someresult1.split('<br>');
        for (var b = 0; b < br.length-1; b++){
            var space = br[b].split(" ");
            array2.push(space[0]);
            array3.push(space[1]);
        }
        for (var v = 0; v < array2.length; v++){
        (function(v) {
            $.ajax({
            url : "http://someurl2.ru/"+array2[v]+"_"+array3[v]+"/",
            async: false,
            success : function(someresult2){
                if(JSON.stringify(someresult2).search(some_array[x]) != -1){
                $.ajax({
                url : "http://someurl3.ru/"+array2[v]+"/"+array3[v]+"/"+some_another_array[x]+"",
                async: false,
                success : function(someresult3){
                    array4.push(someresult3);
                }
                });
                }
            }
            });
            })(v);
        }
    }
    });
})(x);
}

I need to activate async in my request because it freezes my page and slowing down work of the program. There some explanation about program work:

1. Take first element of array1.
2. Creating link and sending request.
3. Taking result and doing some stuff with it.
4. Creating link and sending request.
5. Taking result and doing some stuff with it.
6. Creating link and sending request.
7. Taking result.
8. AND ONLY NOW we take second element of array1 and doing the same.

I need of synchronuous/continuous ajax requests (with "wait" result) in loop.

Answer 1

I just restructured the way you request URLs and the kind of callback. Alert me if something isn't right. Although, I didn't change the program actions and style. I'm really lazy to make that better.

Instead of loops I made a function to go consuming each array1 item, for example, and the same with the array2 . When one request is done in one of these arrays, the next request starts if existent, else do nothing in array1 and when in array2 it just callbacks to the array1 to do the next array item request with the consume function.

var len = array1.length; // Memorize array1 length

function consume(i) {
    var xhr = new XMLHttpRequest(); // Request
    xhr.open("GET",  "http://someurl1.ru/" + array1[i] + "/" , true);
    xhr.onreadystatechange = function() {
        if(this.readyState === 4) {
            // Status 200 is success
            if(this.status === 200) {
                // `this` invokes the `xhr` object
                // Your success block is here
                successCallback(i, this.responseText);
                // Consume next array1 items if length isn't ranged
            }else{
                // Error block is here; can be 403, 404, 500+, ... etc.
            }
        }
    }
    xhr.send()
}

consume(0);

function consume2(i, array2, array3, arrayLen, callback) {
    var xhr = new XMLHttpRequest(); // Request
    xhr.open("GET",  "http://someurl2.ru/" + array2[i] + "_" + array3[i] + "/", true);
    xhr.onreadystatechange = function() {
        if(this.readyState === 4) {
            // Status 200 is success
            if(this.status === 200) {
                // Your success block is here
                if(JSON.stringify(xhr.responseText).search(some_array[i]) !== -1){
                    var xhr2 = new XMLHttpRequest(); // Request
                    xhr2.open("GET", "http://someurl3.ru/" + array2[i] + "/" + array3[i] + "/" + some_another_array[i], true);
                    xhr2.onreadystatechange = function() {
                        if(this.readyState === 4) {
                            // Status 200 is success
                            if(this.status === 200) {
                                // Your success block is here
                                array4.push(xhr2.responseText);
                                // Consume next array2 items
                                if(i < len)
                                    consume2(++ i)
                                ;else
                                    callback()
                            }else{
                                // Error block is here; can be 403, 404, 500+, ... etc.
                            }
                        }
                    };
                    xhr2.send()
                }
            }else{
                // Error block is here; can be 403, 404, 500+, ... etc.
            }
        }
    }
    xhr.send()
}

function successCallback(f, data) {
    array2.length = 0;
    array3.length = 0;
    var br = someresult1.split('<br>');
    for (var b = 0; b < br.length; b++){
        var space = br[b].split(" ");
        array2.push(space[0]);
        array3.push(space[1]);
    }
    consume2(0, array2, array3, array2.length, function() {
        if(f < len)
            consume(++ f)
    })
}

I'll update this code yet, but I don't understand what you surely want to do with it.