Andir Andir - 11 days ago 9
Javascript Question

Is it possible to load in a local version of a JavaScript file instead of the server version?

Just had a quick question to throw out and see if there was a solution for this...

Let's pretend I have no access to the server.
I load up a webpage and find out that they have a Javascript file loading from a subfolder (let's say /scripts/js/some.js)

Now, I want to make changes to this file locally and test it against the whole site without downloading the entire site to a local folder.

Does anyone know of a way I can override the loading of that remote js file in favor of a local/edited copy of it?

Answer

I actually found a solution for this. Posting details for anyone that comes here looking for it.

Privoxy (www.privoxy.org/) [Free] Allows this for the most part through a redirect. Though Firefox may block the redirect depending on where you put it. This means you most likely will not be able to save the file locally and reference it via file://etc/

( I wish I had a way to tell you how to statically fiddle with JavaScript on web pages you have limited access to... but I have not found it. If an answer comes along I will accept it over this. )

Of course, you have to set up Privoxy, and use it as a local proxy server. It's pretty simple if you only use it temporarily: Just point your browser to proxy 127.0.0.1 on port 8118 with it running.

You have to add a redirect "default action" (Options > Edit Default Actions) to redirect the browser to use your new copy:

{ +redirect{/newLocation/some.js} }
 /scripts/js/some.js
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