FineUploader - "isBrowserPreviewCapable" variable not thrown out by Chrome 40, though it should - amazon-s3

Question

I noticed that in the FineUploader server demos (s3demo-thumbnails-cors.php), there is an area that checks if the browser supports preview. It simply checks this post variable: $_POST["isBrowserPreviewCapable"]
The awkward thing here I'd like to ask is, I'm actually using Chrome 40, and I'm absolutely sure that preview is available for my browser. But in the "upload_success" ajax call sent out by FineUploader, it does NOT contain $_POST["isBrowserPreviewCapable"].
Here is a sample dump of my upload success AJAX call. I was wondering if I had missed some sort of configuration for this:
Remote Address:127.0.0.1:80
Request URL:http://localhost/development/code-base/ci/builds/xyz/en/file/api/notify_successful_upload
Request Method:POST
Status Code:200 OK
Request Headers
Accept:application/json
Accept-Encoding:gzip, deflate
Accept-Language:ja,en;q=0.8,en-US;q=0.6,zh;q=0.4,zh-TW;q=0.2,zh-CN;q=0.2,ko;q=0.2
Cache-Control:no-cache
Connection:keep-alive
Content-Length:614
Content-Type:application/x-www-form-urlencoded
Cookie:PHPSESSID=952ciound37e9dkaf5d1hmmc1; __atuvc=10%7C5; CKFinder_Path=Attachments%3A%2F%3A1; logged_in=9db847c22b2bef66cc06091e355a80e6aff83b7d377; abc_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%2244ef7cfb140643bdb09df62f0e9c3561%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A9%3A%22127.0.0.1%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A109%3A%22Mozilla%2F5.0+%28Windows+NT+6.1%3B+WOW64%29+AppleWebKit%2F537.36+%28KHTML%2C+like+Gecko%29+Chrome%2F40.0.2214.115+Safari%2F537.36%22%3Bs%3A13%3A%22last_activity%22%3Bi%3A1424977019%3Bs%3A9%3A%22user_data%22%3Bs%3A0%3A%22%22%3B%7Ddc95cd1bb88507af0eb260abe18f380bbd80e1fd; user_locale=en
Host:localhost
Origin:http://localhost
Referer:http://localhost/development/code-base/ci/builds/xyz/en/file
User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.115 Safari/537.36
X-Requested-With:XMLHttpRequest
Form Data
key:clients/abclient/www/gallery/images/w100/_try_90b313b2-9cea-42f3-8332-e6d13071ded3.png
uuid:c9ed8346-43fb-4116-afe6-18867079524e
name:_try (w100).png
bucket:xyz-production
etag:"b2df53409d64b9e1cb9f1e590d2a4bf6"
file_uuid:c9ed8346-43fb-4116-afe6-18867079524e
file_family_uuid:90b313b2-9cea-42f3-8332-e6d13071ded3
file_storage:s3
file_module:gallery
file_type:images
file_variation:w100
file_name:_try_90b313b2-9cea-42f3-8332-e6d13071ded3.png
file_display_name:_try (w100).png
qqparentuuid:90b313b2-9cea-42f3-8332-e6d13071ded3
qqparentsize:44936
qquuid:c9ed8346-43fb-4116-afe6-18867079524e
Response Headers
Access-Control-Allow-Origin:http://localhost
Connection:Keep-Alive
Content-Length:539
Content-Type:text/html
Date:Thu, 26 Feb 2015 18:57:03 GMT
Keep-Alive:timeout=5, max=94
Server:Apache/2.4.9 (Win64) OpenSSL/1.0.1g PHP/5.5.12
Set-Cookie:user_locale=en; expires=Thu, 26-Feb-2015 20:57:03 GMT; Max-Age=7200; path=/
X-Powered-By:PHP/5.5.12
Any help would be greatly appreciated. Thanks!
Cheers,
Thomas

Answer 1

Fine Uploader does not send the POST variable you are speaking of. The S3 demo on http://fineuploader.com/demos includes a line of code that ensures the parameter is sent with the request.
For example, the following option is configured:
uploadSuccess: {
endpoint: "http://s3-demo.fineuploader.com/s3demo-thumbnails-cors.php?success",
params: {
isBrowserPreviewCapable: qq.supportedFeatures.imagePreviews
}
}