This document explains all of the optionspreferences available in the Advanced panel of the OptionsPreferences window of Mozilla Firefox. To access the optionspreferences window, In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings. . For other panels, see OptionsPreferences window.

The Advanced panel contains optionspreferences for settings that aren't used that often, such as checking to see if Firefox is the default browser, clearing the disk cache, settings for Firefox updates, and various advanced settings that only certain people may need.

General tab

Accessibility

• Always use the cursor keys to navigate within pages: When this optionpreference is enabled, Firefox will display a movable cursor in web pages, allowing you to select text with the keyboard. You can toggle this mode by pressing F7.

• Search for text when I start typing: When this optionpreference is enabled, Firefox will find within the current web page what you type as you type it. While you are finding typed text in the page, the Find Toolbar will automatically display at the bottom of the window to show information about what you've found.

• Warn me when websites try to redirect or reload the page: When this optionpreference is enabled, Firefox will prevent websites from redirecting you to another page, or automatically reloading.

Browsing

• Use autoscrolling: Autoscrolling is a useful feature which allows you to scroll the page by clicking the middle mouse button (usually the scroll wheel) and moving the mouse up or down. Some people find this annoying, so autoscrolling can be disabled with this optionpreference.

• Use smooth scrolling: Smooth scrolling can be very useful if you read a lot of long pages. Normally, when you press Page Down, the view jumps directly down one page. With smooth scrolling, it slides down smoothly, so you can see how much it scrolls. This makes it easier to resume reading from where you were before.

• Check my spelling as I type: When this preference is enabled, Firefox will check your spelling and offer possible corrections as you type in web forms. Note that you may need to download a dictionary; to do so, right-clickpress Ctrl and click on any text field, enable spellchecking if necessary, and then use the provided Languages menu to download a dictionary.

System Defaults

• Always check to see if Firefox is the default browser on startup: Select this option if you want Firefox to check whether it is the default browser at startup. This will ensure Firefox is used whenever an application tries to display a web page. You can also click the Check Now button to do a check right now.

Network tab

Connection

Your organization or Internet service provider may offer or require you to use a proxy. A proxy acts as an intermediary between your computer and the Internet. It intercepts all requests to the Internet to see if it can fulfill the request using its cache. Proxies are used to improve performance, filter requests, and hide your computer from the Internet to improve security. Proxies are often part of corporate firewalls.

Connection Settings Dialog

• No proxy: Choose this if you don't want to use a proxy.

• Auto-detect proxy settings for this network: Choose this if you want Firefox to automatically detect the proxy settings for your network.
• Use system proxy settings: Choose this if you want to use the proxy settings configured for your operating system. This is the default setting.

• Manual proxy configuration: Choose this if you have a list of one or more proxy servers.

Ask your system administrator for the configuration information. Each proxy requires a hostname and a port number.

• • If the same proxy name and port number are used for all protocols, check Use this proxy server for all protocols.
  • No Proxy For: List of hostnames or IP addresses that will not be proxied.
• Automatic proxy configuration URL: Choose this if you have a proxy configuration (.pac) file. Enter the URL and click okay to save changes and load the proxy configuration.
  • Reload: The reload button will load the currently available proxy configuration.

Offline Storage

Pages you view are normally stored in a special cache folder for quicker viewing the next time you visit the same page. You can specify the amount of disk space the cache can use here. You can also immediately clear the contents of the cache.

• Use up to ... MB of space for the cache: Allows you to specify the maximum size, in megabytes, of the cache on your computer.

• Clear Now: Immediately clears the current contents of the cache, freeing the disk space used by the cache.

• Tell me when a website asks to store data for offline use: Allows websites to store data necessary to be used without an internet connection. If you have previously blocked a website from storing data for offline use and changed your mind, you can click the Exceptions... button. Select the site you want to stop blocking, and click Remove. To remove all websites in the list, click Remove All Sites.

• The following websites have stored data for offline use: After a website has stored data for offline use, you can select it in the list, and click Remove... to delete the data.

Update tab

Firefox can check whether updates to installed add-ons or to Firefox itself are available.

• Automatically check for updates to: By default Firefox automatically checks for updates to itself, to add-ons, and to search engines so you'll always know you have the most up-to-date version. You can change this behavior by changing the appropriate checkboxes here.

• When updates to Firefox are found,
  • Ask me what I want to do: Updates to Firefox are installed automatically by default. Select this optionpreference to manually control how and when updates are installed.
  • Automatically download and install the update: When this optionpreference is selected, Firefox updates will be automatically downloaded and will be installed the next time Firefox is restarted. The Warn me if this will disable any of my add-ons optionpreference determines whether you will be warned before the installation of an update which would require an incompatible add-on to be disabled because no newer, compatible version exists. The warning will allow you to postpone installation of the update, though at the expense of improvements included in it.
    
    If all extensions and themes are compatible or can be updated to be compatible, the Firefox update will be installed. Upon restart you will be asked to install any needed add-on updates so that you can continue to use them.

• Show Update History: Firefox automatically records the updates you have installed. You can view information about these updates by clicking this button.
  Note: You must be running Firefox as an administratorroot or as the user who originally installed Firefox to install Firefox updates.

Encryption tab

Protocols

• Use SSL 3.0: Specifies whether you want to send and receive secured information through SSL3 (Secure Sockets Layer, Level 3), a standard protocol for communicating securely with websites. Disabling it will prevent you from visiting some sites.

• Use TLS 1.0: Specifies whether you want to send and receive secured information through TLS (Transport Layer Security), a security standard similar to SSL3 (Secure Sockets Layer). Disabling it will prevent you from visiting some sites.

Certificates

Certificates help perform encryption and decryption of connections to secure sites.

• When a server requests my personal certificate: Some servers ask you to identify yourself with a personal certificate. In order to do so, they ask Firefox to generate one for you. When you visit the site in the future, Firefox will ask you for which certificate to use. If you wish to have Firefox automatically choose a certificate for you, select the Select one automatically optionpreference.
  Note: A personal certificate can contain personally identifiable information, such as your name or address. It may therefore harm your privacy if you select the Select one automatically optionpreference. If you do, you will not be alerted when a website request your personal certificate, and you may lose the ability to control who can access your personal information.

• View Certificates: Click this button to view stored certificates, import new certificates, and back up or delete old certificates in Firefox.

• Revocation Lists: Firefox can use Certificate Revocation Lists (also known as CRLs) to ensure that your certificates are always valid. Click the Revocation Lists button to manage the CRLs installed on your computer.

• Validation: Firefox may ask an OCSP (Online Certificate Status Protocol) server to confirm that a certificate is still valid. By default, Firefox validates a certificate if the certificate provides an OCSP server. Alternately, you can choose an OCSP server against which to validate all certificates. Click the Validation button to manage these optionspreferences. You will most likely only need to change this if your Internet environment requires it.

• Security Devices: Security devices can encrypt and decrypt connections and store certificates and passwords. If you need to use a security device other than the one in Firefox, click the Security Devices button.

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