Need help cocos2d-x JS assets download problem

Hello
We are building Web Browser game with Cocos2d-x Javascript.
Our game need to download over 30 assets files (png, plist, fnt, …) from server.
And if network speed is not good, some files are failed to download.
So I am going to compress assets file to 1 zip file and download it and uncompress and use it for game.
But I don’t know how can I implement this download logic to coding?
Is anyone have experiences or tips for me?
Thank you
Best Regards