How to cancel/abort jQuery AJAX request?

I know this might be a little late but i experience similar issues where calling the abort method didnt really aborted the request. instead the browser was still waiting for a response that it never uses. this code resolved that issue.

 try {
        xhr.onreadystatechange = null;
        xhr.abort();
} catch (e) {}

When you make a request to a server, have it check to see if a progress is not null (or fetching that data) first. If it is fetching data, abort the previous request and initiate the new one.

var progress = null

function fn () {    
    if (progress) {
        progress.abort();
    }
    progress = $.ajax('ajax/progress.ftl', {
        success: function(data) {
            //do something
            progress = null;
        }
    });
}

The jquery ajax method returns a XMLHttpRequest object. You can use this object to cancel the request.

The XMLHttpRequest has a abort method, which cancels the request, but if the request has already been sent to the server then the server will process the request even if we abort the request but the client will not wait for/handle the response.

The xhr object also contains a readyState which contains the state of the request(UNSENT-0, OPENED-1, HEADERS_RECEIVED-2, LOADING-3 and DONE-4). we can use this to check whether the previous request was completed.

$(document).ready(
    var xhr;
    
    var fn = function(){
        if(xhr && xhr.readyState != 4){
            xhr.abort();
        }
        xhr = $.ajax({
            url: 'ajax/progress.ftl',
            success: function(data) {
                //do something
            }
        });
    };

    var interval = setInterval(fn, 500);
);