We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Natao arisiva ity resaka mitohy ity. Mametraha fanontaniana azafady raha mila fanampiana.

Does firefox prevent sites and javascript code from accessing existing cookies and web sites data when browsing in Private Browsing mode?

  • 1 valiny
  • 1 manana an'ity olana ity
  • 8 views
  • Valiny farany nomen'i cor-el

more options

In Private Browsing mode, the cookies, web site data and history is not maintained. However what about the existing data in firefox cache, like cookies and website cache data, i.e. data and trace that has been collected prior to starting the Private Browsing Mode. Is that shared with the websites too? Is there a mechanism where websites and their javascript code can get access to this data, even in Private Mode?

In Private Browsing mode, the cookies, web site data and history is not maintained. However what about the existing data in firefox cache, like cookies and website cache data, i.e. data and trace that has been collected prior to starting the Private Browsing Mode. Is that shared with the websites too? Is there a mechanism where websites and their javascript code can get access to this data, even in Private Mode?

Vahaolana nofidina

No. Private Browsing mode only means that no personal data is saved to the profile folder. In PB mode a separate in memory cookie jar is used, so websites can't access cookies created during a regular session. In all other ways there is no difference in handling cookies and their allow/block exceptions.

Hamaky an'ity valiny ity @ sehatra 👍 1

All Replies (1)

more options

Vahaolana Nofidina

No. Private Browsing mode only means that no personal data is saved to the profile folder. In PB mode a separate in memory cookie jar is used, so websites can't access cookies created during a regular session. In all other ways there is no difference in handling cookies and their allow/block exceptions.