Allowing only certain sites to use JavaScript

From MozillaZine Knowledge Base

This article applies to Firefox and Mozilla Suite

If you prefer to keep JavaScript turned off but need it for a few sites, you can configure the browser to use a JavaScript site "whitelist." There is no built-in interface to do this, but you can use the methods described in this article.


Using the NoScript extension

A user interface for maintaining a site whitelist exists in the NoScript extension. In addition to JavaScript, this extension also allows you to control Flash, Java and other plugins. For additional information, see the NoScript homepage.

Manual configuration

You can manually maintain a JavaScript whitelist by editing the "user.js" file. You can alternatively edit about:config, but due to a bug you will not see the changes you've made (although they will take effect).

In user.js, add the following lines:

user_pref("capability.policy.policynames", "jsok");
user_pref("capability.policy.default.javascript.enabled", "noAccess");
user_pref("capability.policy.jsok.sites", "");
user_pref("capability.policy.jsok.javascript.enabled", "allAccess");

The line with capability.policy.jsok.sites can have multiple websites separated by spaces, like so:

user_pref("capability.policy.jsok.sites", "");

(Naturally, you would replace and with sites you wanted to whitelist.)

Note that you need to have JavaScript enabled when you use these preferences, because disabling it will override these settings.

Similarly, you can create a JavaScript site "blacklist" — that is, allow JavaScript on every site but those you specify. For this behavior, you would add the following lines to user.js:

user_pref("capability.policy.policynames", "nojs");
user_pref("capability.policy.nojs.sites", "");
user_pref("capability.policy.nojs.javascript.enabled", "noAccess");

These examples were taken from the CAPS documentation.

You need to restart your browser after editing user.js, otherwise the changes will not take effect.

See also

External links