Trouble setting expiration for static asset in nginx

I have the following location directive in my nginx config file:

server{
  ...
  location ~* \.js$ {expires 1d;}
  .开发者_C百科..
  location / {
  ...
 }
}

I expect a file served by this URL http://www.mydomain.com/javascripts/myfile.js to have an expiration of +1 day, but I am seeing an expiration of +20 years. What am I doing wrong?

It turns out that I was supposed to edit proxy.conf. Once I did that, it worked swimmingly.