Browser-level DNS settings, to work like the hosts file at system level

Question

The web application we develop is doing certain things depending on the domain and subdomains in the address. To be able to develop and test everything on a local environment, one would need to bind the domains to 127.0.0.1, using the hosts file.

However, this would cut that machine off from accessing the live server domains.

Question: Is there a browser-level hack that allows one to do hosts-like stuff, only for that browser?

UPDATE: A proxy .pac file can do this just fine. Like this:

function FindProxyForURL(url, host) {
      if (shExpMatch(url,"*.example.com/*")){
         return "PROXY 127.0.0.1:80";
      }
   }

Yay!

Answer 1

You can do pretty clever things with a proxy auto-config file. Try one that returns PROXY 127.0.0.1:80 for the domains you want affected and DIRECT for the rest.

Answer 2

Maybe there's a HTTP proxy that will do what you want?