Ideas for a password protected zip file

I need to implement a solution for protecting a .zip file on a web server, using only javascript... Unfortunately, I can't use PHP, ASPX or any other server-side solution. Here's the idea I had, I'd like your feedback or other ideas. The encrypted information is not confidential, but we still need minimal protection.

I had the idea to upload an encrypted version of the file. Then I would use the MD5 result of a password as a key to decrypt the file for the user.

I saw the JSZip framework that could help me. Any thoughts on this idea or other possible solutions?