gistfile1.js

for (var i = 0, l = e.dataTransfer.files.length; i < l; i++) {
    var file = e.dataTransfer.files[i],
    xhr = new XMLHttpRequest;
    xhr.open('post', 'upload.php', true);
    xhr.onreadystatechange = function () {
        if (this.readyState != 4) {
            return;
        }
        // ...
    }
    xhr.setRequestHeader('Content-Type', 'multipart/form-data');
    xhr.setRequestHeader('X-File-Name', file.fileName);
    xhr.setRequestHeader('X-File-Size', file.fileSize);
    xhr.send(file);
}