HTML5/JavaScript bandwidth speed test for mobile app

I am struggling with one problem since a couple of days.

I am developing a mobile app in HTML5. My client wants to add a Bandwidth Speed Test option on it.

So I started looking around on the web, what was done, I found out that almost everything its done using ADOBE FLASH ... wont work... it needs to be Javascript/HTML5.

I found this:

http://ift.tt/2fsG5oY

I tried to use it but ... I receive an error during the download test:

(console output of the example page)

• [Download] Restarting measures with 10.000 MB of data
• [Download] The minimum delay of 8.000 seconds has not been reached
• [Download] Restarting measures with 10.000 MB of data...
• [Download] Final average speed: NaN MBps [Download] Finished measures

I sincerily dont know what the problem is, I tried to debug the code but I could not get with the reason of this NaN (Not a Number) Error.

Any Help? Suggestions? Other solutions?

Remember I am developing a mobile solution (html5)