This article explains the settings available in the Advanced panel of the Firefox OptionsPreferences window. These are settings that aren't used often, such as checking to see if Firefox is the default browser or various advanced settings that only some people 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. This mode is known as Caret Browsing and 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.

• Use hardware acceleration when available: Firefox can use your computer's graphics processor to display some pages with video and animation. This makes Firefox faster since your computer's graphics processor is much better than your computer's main processor at displaying these types of things. This box is checked by default but the feature isn't available for all graphics processors. Firefox will enable it when possible. Read more about hardware acceleration.
  If you change this setting you must restart Firefox.
  To restart Firefox:
  1. Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit.
  2. Start Firefox the way you normally do.

• 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.

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.

Update tab

Certificates help perform encryption and decryption of connections to websites.

• 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.

• 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.