Q:

Is it possible to obtain the download progress of an dynamically loaded javascript file? 

I'd like to load a basic homepage for a web-app which asynchronously loads a large javascript file (the guts of the application). 
Can I retrieve the download progress of this js file?   
I would like to display a loading bar that accurately reflects the download progress, then when the script has finished enable a 'launch' button. 
I normally use jquery but am happy for any solutions!   I'll be using a php backend if that helps. 

A:

This won't work on all browsers, but you can use the <progress> tag in HTML5. 
http://blog.greweb.fr/2012/04/work-in-progress/
You can also use the progress event for the connection. 
https://developer.mozilla.org/En/Using_XMLHttpRequest#Monitoring_progress

