使用AJAX上传DMG文件

I have an uploader

JS Part:

function uploadData(data){
     var xhr = new XMLHttpRequest();
     var fData = new FormData();
                for (var k1 in requestData)
                    if (requestData.hasOwnProperty(k1))
                        fData.append(k1, requestData[k1]);
     xhr.open("POST", "ajax/upload", true);
     xhr.send(fData);
}

And PHP part:

$fileContent = file_get_contents($_FILES['file']['tmp_name']);
file_put_contents(FILES_PATH."/".$_POST['name'], $fileContent);

I also have a form on html. After click upload button:

var file = document.getElementById('files').files[0];
var ext = file.name.split(".").pop();
var name = getRandomString(5) + "." + ext;
uploadData({"file": file, "name": name});

It works with all files (I tested png, jpg, pdf, doc... mp3) but it doesn't work with .DMG extension. I tested everything. In xhr i used a console and i saw that file exists. When i tried to see $_POST, $_REQUEST or $_FILES content i didn't see my .dmg file..