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What is this?

This is an add-on for the Mozilla Firefox or for the Google Chrome. The PP Interrupter interrupts web-navigation to specified URLs in order to Protect Privacy.

This add-on is a general purpose add-on that temporarily blocks access to specified URLs and releases the block by clicking the icon in the address bar. You can habituate yourself to stop once before automatic redirection. Unlike other blockers, this add-on is intended to block healthy sites, not malicious sites.

There is the PP Interrupter (Original) in the Firefox for PC, and besides that there is a function-restricted version i.e. the PP Interrupter Lite.

On the Firefox for PC, by some possibility, if you decide not to continue the blocked page, you can cancel it by clicking the "Stop" button of the browser.

Where can you get it?

For the Firefox for PC, please visit the AMO (Mozilla Add-ons) page where the PP Interrupter (Original) is available. In the case of the Firefox for Android, the PP Interrupter Lite is available on the AMO page. For the Chrome, you can get the PP Interrupter Lite from the Chrome Web Store page.

I made them in accordance with the Web Extension standard which is the standard of browser extension. The number of supported browsers should increase in the future.

Why is it necessary?

The sites that we always use may suddenly attempt to steal data about an authentication provider with malice. They might try to look at our privacy.

What we really want to do is to prohibit automatic redirection to malicious sites. However, it is difficult to judge whether it leads to a malicious site. Therefore, with the idea of reversal, we habituate ourselves to temporarily block access to a healthy site (authentication provider) which is easy to judge, so that by not having a block which we must have it is detected to be guided by a fraudulent site.

The PP Interrupter can be used for such purpose.

Because of difficulties of implementation, the PP Interrupter will block all access to authorities (authentication providers), not just automatic redirections. However, transition from the URL of the authority to the same URL is not blocked. Also, it is possible to register add-ons (extensions) like the PP Authorizer so as not to block access. However, as described below, it is necessary for the add-on to be programmed to be compatible with the PP Interrupter.


To install, you need to download this add-on from the AMO to the Firefox and register the URLs to be blocked on the add-on's "Options" screen. Click the "New Authority" button, enter the identifier name and the URL and save. If you have already installed the PP Authorizer and you want to block the authorities (authentication providers) registered in it, you can click "Add from PP Authorizer" button.

When a URL registered here are checked, it is basically a forward match, but the following character must be a "/", "?" or "&;amp". For example, when the URL is "", it matches "https: //" or "".

The PP Authorizer is a sister product of the PP Interrupter, and an ingredient of Privacy-Protected logins or payments. The PP Authorizer checks each page to have "A" tags or "INPUT hidden" tags having "pp-authorizer" class and prompts to move to their links. For example, using it in the middle of OAuth makes it more secure.

The PP Interrupter is set not to block access by using the PP Authorizer by default. If you accidentally erase the PP Authorizer in the "Allowing Extensions" of the "Options" screen, please click the "Add from PP Authorizer" button or click the "New Extension" button and enter the following contents and "Save" it.

name:         PP Authorizer
extension ID: {783dadb1-a4ec-46e7-a6de-26432b3393c2}

Even without using the PP Interrupter, it is better to have a future in the world that access is stoppped on the page that should use PP Authorizer before authentication. The PP Interrupter is a response to reality, but the PP Authorizer is an investment to the future. However, because the PP Interupter is generic, the PP Interrupter works even without the PP Authorizer.

Register other extensions

To prevent other extensions (add-ons) from being blocked by the PP Interrupter, you need to do something special on the other extension side, in addition to registering the identifier name and the extension ID with the "New Extension" button on the "Options" screen. Since this point is related to programming, general users do not need to read this section.

Other extensions can apply to the PP Interrupter not to block access to the next URL of a tab. Program in the extension as follows. Suppose the variable "tabId" contains the ID of the tab and the variable "url" contains the URL you want to go to.


const PP_INTERRUPTER_ID = "{c35621af-46f1-4338-a8b6-c26bba37fb98}";

browser.runtime.sendMessage(PP_INTERRUPTER_ID, {
  type: "permit",
  tabId: tabId,
  url: url
}).then(x => {
  browser.tabs.update(tabId, {url: url});
}).catch(e => {
  browser.tabs.update(tabId, {url: url});


Apply for permission with "sendMessage" and "x" is set to true if permission is obtained. Make actual page transition with "browser.tabs.update". The programming is done so that page transitions will occur even if the PP Interrupter doesn't exist in the browser.

Differences between the PP Interrupter (Original) and the PP Interrupter Lite

The PP Interrupter Lite is a function-restricted version.

The PP Interrupter (Original) can block all methods such as "GET" or "POST" of web requests, but the PP Interrupter Lite can only block "GET" method.

The PP Interrupter (Original) is displayed by the notification function of the browser, whereas the PP Interrupter Lite displays the page halfway. If you are annoying about notifications and want to be displayed on the page, you can also select the PP Interrupter Lite in the Firefox for PC.

This add-on is somewhat experimental

This add-on has just been made and is somewhat experimental. However, since it was able to be used for general purpose from the beginning, it should be more practical compared with the PP Authorizer. It is appreciated if you try to use the PP Interrupter.

Since the author himself does not use a site that automatically redirects to an authentication provider, he doesn't have the opportunity to experiment this add-on. Therefore, updating this add-on is expected to be prone to stagnation. I want you to forgive me.

Opinions and requests are accepted on one page of the author's blog. It is a Japanese site, but you can comment in English. Because it is an individual site, there must be many difficulties, I think. I need your tolerance.

(This English page has been made of sequentially modified paragraphs of the translated ones by the Google translation of the Japanese page.)


The author is a Japanese.

I intended this program to be public-domain, but you can treat this program under the (new) BSD-License or under the Artistic License, if it is convenient for you.

Within three months after the release of this program, I especially admit responsibility of efforts for rational requests of correction to this program.

I often have bouts of schizophrenia, but I believe that my intention is legitimately fulfilled.

(On the Mozilla's distribution page, the BSD License has been chosen for the sake of clarity, but the license can be loosened as above if you like so.)