Downloading progress bar

Downloading progress bar

Hi to all,

My requirement is "when i click on download button the one popup should appear for showing progress values".
for this i need to  implement progress bar for showing correct progress of Downloading file(e.g. 10%, 20%, 30%.... 100%) not any static image.

As i know about the progress bar UI but in this i need to send value to progress bar, but how i will get that value.

Hope u got my point.
If any one have solutions or suggestions, please reply me.

Thanks and Regards,
Amit