Abort AJAX request on button click

I want to abort my AJAX file upload, using XML abort function.

Below is script (jQuery), showing my AJAX request call:

var jqXHR = new window.XMLHttpRequest();
$("#file_uploading").change(function(e) {
    var fullPath = $('#File-upload-0').val();    
    var output = fullPath.substr(0, fullPath.lastIndexOf('.')) || fullPath;
    var filename = output.replace(/^.*\\/, "");
    $('#cancel_btn').removeClass('hidden');
    //console.log(filename);
    $('#f_name').val(filename);
    $('#reupload_block_cl').addClass('alert-success').removeClass('alert-danger');
    $('#loader').removeClass('hidden');
    e.preventDefault();
    $.ajax({
        url: window.reuploading_file,
        type: "POST",
        data: new FormData(this),
        contentType: false,
        cache: false,
        processData: false,
        success: function(data) {
            //alert(data.success);
            if (data.success) {
                $('#cancel_btn').addClass('hidden');
                $('#loader').addClass('hidden');
                $('#reupload_block_msg').html(data.success);
                $('#reupload_block').removeClass('hidden');
            }
        }, 
        error: function(data) {
            //alert(data.success);
            var obj = jQuery.parseJSON(data.responseText);
            var str = obj['file'][0];
            if (str.startsWith("The file may not be greater than")) {
                $('#loader').addClass('hidden');
                $('#cancel_btn').addClass('hidden');
                $('#reupload_block_msg').html(str);
                $('#reupload_block_cl').addClass('alert-danger')
                    .removeClass('alert-success');
                $('#reupload_block').removeClass('hidden');
            } else {
                $('#loader').addClass('hidden');
                $('#cancel_btn').addClass('hidden');
                $('#reupload_block_msg').html(str);
                $('#reupload_block_cl').addClass('alert-danger')
                    .removeClass('alert-success');
                $('#reupload_block').removeClass('hidden');
            }
        }           
    });
});

and on the cancel button click, what I want to achieve is: to abort AJAX request.

Below is my cancel button click function script (jQuery) which is not working as expected:

$('#final_upload').on('click', function() {
    jqXHR.abort();
    $('#loader').addClass('hidden');
});

What am I doing wrong and how can I resolve it?

Check this.

http://api.jquery.com/jQuery.ajax/#jqXHR

The jqXHR object is not var jqXHR = new window.XMLHttpRequest();.

It should be var jqXHR = $.ajax(param);