Do you ever have that feeling where you’re on a website and you can’t help but wonder if the site is watching what other tabs you have open? It seems like a bit of a paranoid thought, but is it really possible for a website to track which other tabs are open in your browser? In this article, you will get the answer.
Websites can’t access data on the other tabs; this is by browser-design and can’t be circumvented. However, there might be situations where your browser-cookies might give away little pieces of information. If two distinct websites utilize the same advertising or tracking network, your surfing history across both sites may be tracked and linked.
Why websites can’t access information of other tabs?
As mentioned before this prevention is by design. It’s a security feature to prevent websites from being able to snoop on your activity. If a website could see what other tabs were open it would represent a significant privacy and security concern.
There are a few reasons:
- The browser may be designed to not allow it
By design, websites are not able to access information from other tabs. This is a security measure to prevent malicious sites from snooping on your activity.
This is true for all common browsers. For example. All Chromium-based browsers—including Google Chrome, Microsoft Edge, and Opera—have this security measure in place.
The same is true for Safari and Firefox.
- Websites on different tabs are isolated from each other by the same-origin policy
The same-origin policy is a security measure that browsers have in place to prevent websites from accessing data from other sites.
Under the same-origin policy, a website can only access data from another site if they share the same domain, protocol, and port.
For example, a website on the domain „example.com“ would not be able to access data from „example.org“, even if both sites use the same protocol (e.g., „HTTPS“) and port (e.g., „443“).
- The browser may provide an API that blocks access to data from other tabs
Some browsers provide an API that allows websites to explicitly request information about other tabs, but this is not generally enabled by default and would require you to opt-in.
For example, the „Tab sharing“ API in Google Chrome allows websites to request information about which tabs are open in your browser, but this feature is disabled by default and must be explicitly enabled by the user.
- It would present too much of a security risk
If websites were able to access information from other tabs, it would present a major security risk.
For example, a malicious site could snoop on your activity in other tabs and steal sensitive information like passwords or credit card numbers.
It could also use this information to track your browsing habits across multiple sites.
This would be a major violation of your privacy and could have serious security implications.
Therefore, it’s important that websites are not able to access information from other tabs. This is a security measure that is in place to protect your privacy and keep your data safe.
So while websites can’t track which other tabs are open, they may be able to infer it in some cases. However, this is not something that happens by default, and there are ways to prevent it.
Potential ways a website could infer you have other tabs open
Now let’s have a look at how a website might be able to infer that you have other tabs open, even though they can’t access the data directly.
There are a few potential ways:
- If the site has third-party cookies enabled and shares a common advertising or tracking network with another site, it’s possible that your browsing history across both sites may be tracked and linked.
- If you’re logged into the same account on multiple tabs, a website could conceivably detect this by checking for the presence of cookies associated with your account.
- Some browsers provide an API that allows websites to explicitly request information about other tabs, but this is not generally enabled by default and would require you to opt-in.
How to prevent being tracked by the sites you visit
If you’re concerned about being tracked by the sites you visit, there are a few things you can do to prevent it.
Don’t opt-in for sharing other tabs information
First and foremost: don’t accept opt-ins blindly. If a website asks you to enable the „Tab sharing“ API or any other permission that would allow it to snoop on your activity, think carefully before doing so.
Only grant these permissions to sites that you trust, and be aware of the implications of doing so. I recommend not doing so at all as there is pretty much no scenario where this really should be necessary.
Disabling third-party cookies
Futher, you can disable third-party cookies in your browser settings. This will prevent sites from sharing information with each other and tracking your activity across multiple sites.
Using a browser that blocks access to data from other tabs
There are several privacy browsers you can use that have built-in features to prevent websites from accessing data from other tabs. For example, the Brave browser blocks access to this data by default.
Using private mode
You can also use a private browsing mode, which will prevent sites from storing cookies or tracking your activity.
Clearing your browser cookies when closing your browser
You can also clear your browser cookies whenever you close your browser. This will prevent sites from storing any information about your activity.
All common web browsers do have a setting for this.
Using a privacy extension
Finally, you can install an ad blocker or privacy extension, which will block third-party cookies and other tracking methods.
If you are not using Brave Browser, you can install a privacy extension like Privacy Badger or Ghostery. These extensions will block third-party cookies and prevent sites
By taking these steps, you can make it more difficult for websites to track your activity and protect your privacy.