Recurring jquery ajax calls - php

Question

I have multiple check boxes for users to select and based on selected checkboxes i need to make a jquery ajax call. For that i used FOR loop to iterate through selected elements array and sent ajax request for each checkbox. Each request takes more than 5-10 minutes. In current scenario it calls all ajax request simultaneously.
I want to call next ajax calls only after finishing earlier ajax request.
Is there any solution for this?

Answer 1

You can make recursive calls.
function sendAjax(id) {
var checkbox = $('input[type=checkbox]:eq('+id+')','#formid');
if(checkbox == undefined)
return;
$.ajax({
type: 'POST',
dataType: "json",
url: 'url',
data: { },
success: function (data) {
sendAjax(id+1);
},
error: function (data) {
alert(data.responseText);
}
});
}
sendAjax(0);

Answer 2

Iterate in your readyStateChange method instead of in the for loop.
...
array_index++;
var data = selected_elements[array_index];
if (data) {
send_ajax_request(data);
}
}

Answer 3

That is kind of against the whole point of ajax. The first "a" is usually considered to mean "asynchronous", but you want to make the request synchronous (async = false I believe in jQuery)

Answer 4

Using recursive call, until previous ajax request not finished, next request cant be processed. So recursive call can solve the problem of these ajax request.
var queue_element = ["a","b","c","d","e","f","g"];
var execute_queue = function(i){
$.ajax( {
url: queue_element[i],
success: function({
i++; // going to next queue entry
// check if it exists
if (queue_element[i] != undefined){
execute_queue(i);
}
}
}); // end of $.ajax( {...
}; // end of execute_queue() {...
var index = 0;
execute_queue(index); // go!