Mozilla Firefox is one of the most popular web browsers in the world. As with any web browser there is a lot of data collected as you browse the web. These set of data contains many different types of information: the browsing history, the site cookies, the cache, and personal data among others.
Many times you might want to delete all or some of the private data that is stored in the browser. Removing such private data can be done manually, but if you want to do it routinely then it is a good practise to automate the process. Mozilla firefox provides you with the option to delete the stored private data everytime you shutdown the browser.
Click on Firefox Menu and Click Preferences
Click on the Privacy Tab
Under the History section, select the custom settings option
You will now see the option to Clear History when Firefox closes. Select the checkbox next to it.
Now, you have some options that let you decide which of the private data should be deleted automatically when you close the browser. Click on the Settings button next to the selected option. The settings dialog popup will now let you pick and choose the set of data that you deleted.
There are several different data types that you can choose from. All of the options are pretty much self-explanatory and select them with the checkboxes next to each of them. The options you have are
Browsing and Download History: This will delete that information regarding the websites you have visited in the past and also the history about the files you have downloaded to your machine.
Cookies: Cookies are small pieces of information that websites store locally in your browser, usually to provide some useful functionality. This can be login data, that allows you to visit websites without logging in each time or a shopping cart which saves information about products you have selected etc. You will have to re-login into websites that you use a cookie based login.
Active Logins: Some websites use an HTTP authentication method to keep you logged in. You can logout of all such websites but it will require you to re-login when you visit those sites again.
Cache: These are all the content that saves locally from the websites you have visited. This data is used to speed up page loading when you visit them again.
Form and Search History: This is data you have manually entered into various forms and search query boxes on various websites. The web browser uses such information to display the quick drop down boxes.
Site Preferences: These are the site specific preferences that you have previously set on the browser. These data could be something like text zoom settings, popup blocker info or character encoding etc.
Offline Website Data: Offline website data is useful if you are browse or access website with an active internet connection.
Most times the private data is used to provide a better user experience. It can increase browsing speed, persist some useful information for convenience etc. Nevertheless it is still a security hole and a privacy concern. Sometimes, cleaning up old and stale data can actually speed up your browsing experience and browser performance.