AdTab Killer

How it works #

AdTab Killer does not stop tabs and windows from being created. It closes them almost the instant they open. So you will see a flash, or a tab that appears and vanishes. That is it working, not failing.

The one exception is the fullscreen shield, which really does prevent things from opening. It is covered in Fullscreen.

It watches three things the browser reports: a tab was created, a window was created, and a page asked to open something. Then it decides using your lists and your settings.

It is not an ad blocker. It does not remove banners or video ads from a page, and it does not filter content. What it deals with is the tabs, windows and pop-ups that get opened without you asking.

The three lists #

The names do not mean what they look like. Read this table before adding anything to a list.

List	What it actually does
Protected	The site loads normally. What gets closed is whatever that site opens: ad tabs, pop-ups, tabs opened by scripts, shift-clicks. Protected means you are protected while you browse there.
Blocked	The site never stays open. If it arrives on its own it is closed silently. If you go there on purpose you get a warning page.
Allowed	A destination that is always permitted. It is exempt from Protected and from the two global blocks in Settings → Tools.

A site keeps opening ad tabs and pop-ups? It goes in Protected, not Blocked

Putting the site in Blocked blocks the site, not what it opens: you lose the site and keep the problem. Protected is the list that stops a site from opening things.

Either way, nothing here removes ads from the page you are reading. What gets closed is what opens in a new tab or window.

When a site is on more than one list

Strongest first:

Blocked, written out exactly
Allowed, written out exactly
Blocked, matched through subdomains
Allowed, matched through subdomains
Protected, and the global blocks (Block all new tabs and Block all new windows, in Settings → Tools)

So if you have *.example.com in Blocked and you add shop.example.com to Allowed, Allowed wins for that one address: writing a full site out is a stronger statement than a wildcard. But if shop.example.com were written out in both lists, Blocked would win.

Subdomains

Every row in Allowed and Blocked has a switch that adds the *. prefix, so that entry covers the site and all of its subdomains.
There are also two global settings, one per list, both called Include subdomains, which force every entry in that list to cover subdomains.
An entry covers subdomains if the global setting is on or its own switch is on.
Protected has none of this. It always matches the exact site.

Allowed and Blocked cannot both hold a site

Adding a site to one removes it from the other, and a notice tells you so for a few seconds. Protected is a separate question and is not affected.

What cannot be added

None of the three lists accepts the browser's own internal pages (chrome://, edge://, about:), extension pages, the extension stores themselves, or Mozilla's protected addresses. The browser grants no permissions there, so the button is disabled and the field refuses the entry.

Protection: Block or Strict #

Settings → Tools & protection → Ads that open a blank tab first. Two options, and each one gives something up. Read both before changing it.

The trick it exists for: the ad calls window.open() with no address, which opens a blank tab, and only a moment later sends that tab to the ad. At the instant it opens there is nothing to judge, because there is no destination yet.

Block, the default

The extension notes where the tab came from and waits for it to reveal its first real destination, then decides. What that costs and buys:

The ad does get requested. The request reaches the network.
In exchange, Allowed and Allow same site tabs can save the tab, because now there is a destination to compare them against.
Tabs that never reveal a destination, such as a PDF viewer or the print window, survive: after ten seconds they are left alone.

Strict

It closes immediately, without waiting:

The ad never gets requested.
But with no destination there is nothing to consult, so Allowed rescues nothing.

On a Protected site, Strict also closes payment windows, external sign-in windows (Google, Facebook and similar) and PDF windows. If a checkout keeps disappearing, this is almost always why. Switch it back to Block.

A normal Ctrl-click never goes through any of this: that event already carries the address with it.

Strict is part of Pro: without it, choosing Strict shows a gold notice and nothing changes.

Fullscreen #

Settings → Tools & protection → In fullscreen. It only applies to sites that are in Protected.

Strict, the default. The only case where the extension prevents instead of closes. While the page is fullscreen it intercepts window.open and synthetic clicks on target="_blank" links, and blocks new navigations that that site starts. That is how you keep the video fullscreen.
Block. The normal close-after-opening behaviour; fullscreen changes nothing. Note that closing the tab does not put the video back into fullscreen: the browser already took you out when the tab opened. That is why the default is Strict.
Don't block. Nothing is closed while you are in fullscreen.

Where it falls short

If a fullscreen site performs a real navigation, meaning it changes page rather than switching an internal view, Strict blocks it. This is rare during playback, but it happens.
Many ads open from the player's own frame. The shield is planted in every frame when fullscreen starts, but if the outer page owns the fullscreen over the frame's element, rather than the frame owning it over its own content, that frame's shield does not activate.
Blocks made by a network rule cannot be recorded in the activity log. That is a limitation of the browser API. Only what the in-page shield intercepts shows up there.

Two settings have an option called Strict, and two have one called Block. They are not the same thing. When you look something up, use the full name: Ads that open a blank tab first: Strict is not In fullscreen: Strict.

Links to the same site #

Allow same site tabs is on by default. With it on, a link that opens a page on the same site you are already looking at is not closed.

Turn it off and those links close like any ad. That is the one close you did not ask for, and with no explanation it looks broken, so a notice appears in the top right of the page with a button that turns the setting back on without opening the popup.

It appears in that case only. Closing an ad never shows a notice: those are the ones you wanted.
You can silence it with Remind me on the page, but it comes back every time you turn Allow same site tabs off again.
It does not appear in fullscreen, on purpose.
It can show up again when you reload. Nothing is remembered.
On some pages it cannot appear at all: the browser's internal pages, or Firefox without site access granted. The tab is still closed, you just do not get the notice.

Blocked sites #

What happens depends on who opened it.

It arrived on its own (an ad, a script, a restored session, Ctrl+Shift+T): closed silently.
You went there (address bar, bookmark, reload): a warning page with three choices, continue anyway, remove it from the list and continue, or go back.

Continue anyway lets you move around the site by following links, but reloading or typing the address again brings the warning back. That is deliberate: it is a one-time pass, not a permanent exception.

If closing the tab would quit the browser because it is the last one open, you get the New Tab page instead. Go back does the same.

Adding a site to Blocked takes effect on tabs of that site that are already open. You do not have to reload anything.

All settings #

Open the popup and go to Settings, then the category. Every option below shows the value it ships with, so if you have not changed it, that is what it is doing right now.

Settings → Tools & protection

Ads that open a blank tab first Default: Block: What to do with a tab that a Protected site opens with no destination. See Protection: Block or Strict.
In fullscreen Default: Strict: What happens on Protected sites while the page is fullscreen. See Fullscreen.
Block all new tabs Default: off: Closes every tab any site tries to open, whether or not it is in Protected. This and the next one are what the rest of this page calls the global blocks. Allowed still overrides them.
Block all new windows Default: off: The same for windows.
Allow same site tabs Default: on: Keeps links that lead to the site you are already on. See Links to the same site.
Remind me on the page Default: on: Only visible when the setting above is off. Shows a notice inside the page when a link to the same site gets closed.
Allow extension pages Default: on: Lets other extensions open their own pages even while the global blocks are on.
Include subdomains, Allowed Default: off: Makes every entry in Allowed cover subdomains too.
Include subdomains, Blocked Default: off: The same for Blocked.

The lower part of the Tools & protection settings screen, with the Auto Mute and Auto Reload options. — Further down the same screen: the rules of Auto Mute and Auto Reload.

Auto Mute · Which tabs Default: All but the active one: All but the active one mutes every tab except the one in front of the window you are using. New tabs mutes tabs as they open, until you go to them. New windows mutes the tabs of a new window until you unmute them.
Auto Mute · Site list Default: Off: Only these mutes only the sites in its list. All but these never mutes them. The list has its own page: its row appears below once you choose one of the two.
Auto Reload · Which tabs Default: This tab: This tab reloads the tab you turn it on in, one at a time. Several tabs keeps every tab you turn it on in. All tabs and All but the active one are rules for the whole browser, turned on as one.
Auto Reload · Reload every Default: 5 min: A number (1, 5, 10, 20 or 30) and a unit: seconds, minutes or hours. Exact number lets you type any number from 1 to 999.
Auto Reload · Keep going on other sites Default: on: A tab you turned it on in keeps reloading when it goes to another site. Off, it stops there. It shows under This tab and Several tabs.
Auto Reload · Site list Default: Off: For All tabs and All but the active one. Only these reloads only the sites in its list. All but these never reloads them.

Options with a Pro tag in the popup need Pro: without it, choosing one shows a notice and nothing changes. With Pro, the tags go away.

Settings → Shortcuts

Reuse window Default: Off: Applies to the Tab to Window shortcut. Off always makes a new window. Automatic asks and reuses the first existing window. Manual lets you pick the window from a list.
Close Tabs · Which tabs Default: This window: This window closes the other tabs of the window. Left and Right close only the tabs on that side of the current one. All windows closes the other tabs of every window. The current tab and pinned tabs are never closed.
Keep Allowed sites Default: off: Never closes tabs on the sites in Allowed.
Keep browser pages Default: off: Leaves the browser's own pages open: the new tab page, settings and similar.
Close Tabs · Site list Default: Off: Keep these never closes the sites in its list. Only these closes nothing but them.
Ask before closing Default: off: Asks first when it would close more than a number of tabs that you choose, 5 unless you change it.

Settings → Appearance

Setting	Values	Default
Style	Classic, Modern	Modern
Theme	System, Light, Dark	System
True black	on, off	off
Accent	Green, Teal, Ocean, Iris, Fuchsia, Graphite	Green
Navigation bar	Bottom, Top	Bottom
Title bar	on, off	on
Open on	Home, Shortcuts, Tools, Settings	Home
Shortcuts per row	3 to 6	3
Styled tooltips	on, off	on
Skip what's new	on, off	off

Style switches the whole popup between Modern and Classic at once, without closing it. Both keep the same settings and the same lists.

At four or more per row the buttons switch to icons only. There is no separate setting for that.

Settings → Help

Help opens this page. About has the version number, a link to the changelog, a link to replay the welcome tour, and a link to rate the extension on the store you installed from.

To reach us, write to support-adtabkiller@htmyname.dev.

Tools and shortcuts #

Tools holds your three lists, Activity, and two tools that are switches: Auto Mute and Auto Reload. Both are off until you turn them on. Their rules are in Settings → Tools & protection.

Auto Mute mutes every tab except the one in front of the window you are using. Switch tabs and the new one plays while the one you left goes quiet, so only one tab plays in the whole browser. It never overrides you: it unmutes only what it muted, and a tab you unmuted yourself stays that way. Turn it off and everything it had muted plays again.

Auto Reload reloads the tab you turn it on in at the interval you chose, 5 minutes unless you change it. Turn it on in another tab and it moves there. While it is on, that tab shows a ↻ mark on the extension's toolbar icon.

A reload throws away whatever you were typing in the page, so Auto Reload never starts on its own: switching between reloading tab by tab and a rule for every tab leaves it off until you turn it on again in Tools. Reloading tab by tab also ends when you close the browser.

Shortcuts has three that work. Tab to Window pulls the current tab out into its own window, or sends it to another one depending on Reuse window.

Close Tabs closes the other tabs of the window, never the current one and never pinned ones. The popup closes and a notice inside the page offers Undo, which reopens them where they were, without their back history. Only the last close can be undone.

Playing Tab takes you to the tab that is playing sound, in whichever window it is. With several playing, each press goes to the next one. A muted tab that is still playing counts too.

In Firefox, Close Tabs leaves Firefox's own pages open (the new tab page, settings): Firefox does not let an extension reopen them, so Undo could not bring them back.

Tab Limit, Auto Discard, Copy URLs and Save Session are marked as coming soon. There is no date for any of them.

Activity logs #

Tools → Activity shows what was closed today, newest first, with a search button. Each row has a menu to add that site to Allowed or to Blocked, or to remove it from your lists. The log keeps up to 5,000 entries.

A close can take up to a second to show up, because entries are written in batches. Looking at earlier days is part of Pro; the menu of each row works for everyone.

The log lives in your browser. It is never sent anywhere. See Privacy.

FAQ #

I see a flash, or a tab appears and disappears

That is normal. The extension closes tabs, it does not stop them from opening. The only real prevention is In fullscreen: Strict.

I put a site in Blocked and now I cannot open it

Blocked is for sites you never want to open. To stop a site from opening tabs and pop-ups, the list you want is Protected. See The three lists.

My payment window closed, or my Google sign-in window did

Almost certainly Ads that open a blank tab first: Strict on a Protected site. Set it back to Block, or put the payment site in Allowed, which does rescue it under Block.

I added the site to Allowed and it still closes

Three possible causes:

It is in Blocked, written out exactly, which wins.
It is a subdomain and you have not enabled subdomains for that entry.
You are on Ads that open a blank tab first: Strict, where Allowed cannot act because there is no destination to compare it with.

Links to the site I am already on keep closing

Allow same site tabs is off. Turn it on. The notice that appears in the page has a button that does it for you.

The counter and the history do not match

Entries are written in batches, so give it a second. If the browser shuts down the extension's background process at that exact moment, up to a second of activity can be lost.

I restarted my browser and nothing was closed for a few seconds

On purpose. There is a grace period at startup so that the tabs your browser is restoring do not get killed. It extends while tabs keep arriving, up to one minute.

Ctrl+Shift+T reopens a tab the extension should close

Also on purpose: reopening a tab yourself is told apart from an ad opening one. The exception does not apply to sites in Blocked.

The toolbar icon changed

There is something new in a recent version. It clears when you open the changelog, when you dismiss the notice in Settings, or if you turn on Skip what's new. It only appears on minor and major version jumps, never on a patch.

The popup looks different after an update

Version 1.9 brought a new look, Modern, and it is the default. Nothing was lost: your lists and settings are the same. To go back, open Settings → Appearance → Style and choose Classic.

A tab keeps reloading on its own

Auto Reload is on for that tab: its toolbar icon shows a ↻ mark. Open the popup on that tab, go to Tools and turn Auto Reload off.

A tab went silent

Auto Mute is on: it mutes every tab except the one in front. Go to that tab and it plays. To stop it, turn Auto Mute off in Tools.

I turned global protection off and something is still happening

The switch on Home turns off every guard, the Blocked list included. If something still happens, it is another extension or your browser's own pop-up blocker.

Does it work in private or incognito windows?

Only if you allow it on your browser's extensions page. It does not turn itself on there.

What about Firefox?

There is a Firefox version. Site access is an optional permission there: without granting it, closing still works, but the fullscreen shield and the in-page notice do not. The popup asks for it with a banner.

Troubleshooting #

When something closes that you wanted to keep, go in this order.

Is global protection on? Check the switch on Home.
Is the site in Protected? The big button on Home tells you and changes it.
Open Activity, in Tools. Was the close recorded? If there is no entry, it was not this extension.
If something closes that should not: is the destination in Allowed? Is it a subdomain?
If payment or sign-in windows vanish: set Ads that open a blank tab first back from Strict to Block.
If a video drops out of fullscreen: take In fullscreen up to Strict.
Still unclear? Turn global protection off for a moment and see whether the problem continues. That rules out another extension.

If none of this explains it, write to support-adtabkiller@htmyname.dev and tell us which site it happens on.

Privacy #

Without Pro, the extension sends nothing about you or what you browse. It has no analytics. There is one temporary exception: in Chrome and Edge, version 1.9 tells our servers each time the style of its popup changes, only the style and the extension version, with no account and no identifier, so we can decide how long to keep the classic style. The Firefox version does not send it. Your settings, your three lists, the activity log and the counter live in your browser's local storage.

Pro needs a connection, because a license has to be checked. A Pro install contacts our servers to confirm the license is valid and which installation is using it, and a Pro feature that needs a server would work the same way. Those requests carry what identifies your account and that installation, and nothing about the pages you visit or what got closed.

The permissions it asks for, and what each is for:

Tabs and windows, to see one open and to close it.
Navigation, to see where a tab is going before deciding.
Storage, to keep your lists and settings on your machine.
Script injection, for the fullscreen shield and the in-page notice.
Network rules, to stop a fullscreen page from opening things.

What the account and the license store on our side, and for how long, is in the Privacy Policy.