Disable javascript's domain restrictions in FF 7.0

I am developing a small html + JS app for my own use and being ability to access IFrame's content or opened windows' contect with Javascript would greatly improve my productivity.

Is it possible to disable the cross domain restrictions imposed by Firefox 7.0, so that I will be abl开发者_开发知识库e to modify contents of what is displayed in an iframe?

I think I remember a similar issue a while ago in FF. This is worth a try:

There's a file in your user profile called prefs.js. On my machine its located:

C:\Users\simon\AppData\Roaming\Mozilla\Firefox\Profiles\aoagj1zo.default

In the file are a bunch of lines like this:

user_pref("accessibility.typeaheadfind.flashBar", 0);
user_pref("app.update.lastUpdateTime.addon-background-update-timer", 1317146699);

Try adding this line:

user_pref("capability.policy.default.XMLHttpRequest.open", "allAccess");

You should probably close FF, edit this file, then reopen FF.