How to display percentage for preloading of 6 bin files embed in a web page

[ChemBioScripting]

Good afternoon,
I'm searching for a way to indicate the download time necessary to preload six bin files:

http://grvsitest.altervista.org/media/source/cartoon_html/BG_0_coordBinary.bin
http://grvsitest.altervista.org/media/source/cartoon_html/BG_0_normalBinary.bin
http://grvsitest.altervista.org/media/source/cartoon_html/BG_0_colorBinary.bin
http://grvsitest.altervista.org/media/source/surface_html/BG_0_coordBinary.bin
http://grvsitest.altervista.org/media/source/surface_html/BG_0_normalBinary.bin
http://grvsitest.altervista.org/media/source/surface_html/BG_0_colorBinary.bin

which require the largest time to load the whole web page, which has an incorporated x3d file (not in inline mode). For now, I'm using a timer setted to 75 seconds (an in excess time, considering the variable network connection speed and the emptying or less of user browser's cache), to have the necessary time to finish the web page preloading (as you can see here: http://grvsitest.altervista.org), but when the page is already visited (for which it is in the browser's cache), it requires much less time to see the object, and so it results in a not necessary delay. So, I'm searching for a way to take the real time needed each time to preload these six objects, after which will happen the hiding of the preloader and the showing of the 3D viewer. I found your PxLoader javascript, and I thought that it could be able to do that, but I would ask you how I can pass bin files to display a percentage progress of download, as on click on the header of your website's home page (http://thinkpixellab.com/pxloader/). Thanks a lot for your help, and I hope you can give me some indications.

Regards,

Riccardo