Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

All the current versions of top five web browsers support private browsing mode, where they don't save anything as history or cache or cookies. But do they use cache saved from previous normal session?? suppose I open Facebook in normal mode and all the assets of webpage are cached, now, I open it up again in private mode, will my browser use the same cache it stored earlier ? also, does same apply for cookies?

share|improve this question
up vote 2 down vote accepted

No and no. That's the entire point of private browsing.

Wade was right and I was wrong. According to research, browsers tend to leak information, especially through add-ins.

The researchers found that the browsers' protections were imperfect. Browsers did not properly isolate their private sessions from non-private ones, with the result that suitably crafted sites could trace visitors between private and non-private sessions. Sites could also leave persistent indications that they had been visited, allowing visits to be detected by local users.

As Wade also pointed out, Firefox will reuse non-private in-memory cache for sites that are then visited in privacy mode.

share|improve this answer

Randolph you are incorrect. I just tested firefox 10. It uses in-memory cache of pages and websites. It does not use the on-disk cache.

Good point about the addons :)

share|improve this answer
I have updated my answer. – user3463 Jul 28 '12 at 4:17

Chrome incognito windows also use cached static assets from previous non-incognito browsing sessions, without restraint. (A quick look at the Network tab in Dev tools demonstrates this). In my quick check, it also appeared that clearing the cache had no effect on any open incognito windows--they still used the cached assets! In sum, Incognito isn't currently a useful tool for loading pages "from scratch".

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .