I know there are a lot of similar questions, but I still haven't found a solution for my problem.
I'm trying to upload a file with XMLHttpRequest, so I developed the code below:

var sendFiles = function(url,onload,onerror,file,headers){

    var xhr = XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHttp'),

    upload = xhr.upload;

    API.addEvent(xhr,'readystatechange',function(){

        if(xhr.readyState==4)

            if((xhr.status>=200 && xhr.status<300) || xhr.status==304){

                this.response = this.response || this.responseText;

                onload.call(xhr);

            }else onerror.call(xhr);

    });

    xhr.open('POST',url,true);

    for(var n=0;n<headers.length;n++)

        xhr.setRequestHeader(headers[n]);

    xhr.send(file);

    return xhr;

};

And the PHP-side script is:

<?php

header('Content-type: text/html;charset=ISO-8859-1');

$status = 0;

if(@copy($_FILES['file']['tmp_name'],'test\' . $_FILES['file']['name']))

    $status = 1;

else

    $err = '0';

echo '{

    status: ' . $status . '

}';

?>;

But the var $_FILES['file'] seems to be empty, which means that the file isn't being sent to the server.
Then i decided to use the FormData Object, in the code below

var sendFiles = function(url,onload,onerror,file,headers){

    var xhr = XMLHttpRequest ? new XMLHttpRequest() : new    ActiveXObject('Microsoft.XMLHttp'),

    upload = xhr.upload,

    formData = new FormData();

    formData.append('file',file);

    API.addEvent(xhr,'readystatechange',function(){

        if(xhr.readyState==4)

            if((xhr.status>=200 && xhr.status<300) || xhr.status==304){

                this.response = this.response || this.responseText;

                onload.call(xhr);

            }else onerror.call(xhr);

    });

    xhr.open('POST',url,true);

    for(var n=0;n<headers.length;n++)

        xhr.setRequestHeader(headers[n]);

    xhr.send(formData);

    return xhr;

};

And it worked, but only with file sizes low to about 8mb. When I try sending a file that has more than 8mb of size, the var $_FILES['file'] becomes empty again



NOTE: the 'file' var corresponds to something like document.getElementsById('fileInput').files[0];