Applies to: Communicator
4.0x
Operating Systems: Windows 3.x, Windows 95, and Windows NT.
ADVANCED COMMUNICATOR PREFERENCES
user_pref Settings for the prefs.js Configuration File
IMPORTANT NOTE: This page contains information regarding direct
modification of the core Communicator preferences file, prefs.js. This
file is located in your ...\Netscape\Users\{username}\ directory. Before
making changes to this file, Netscape must not be running, you should
always make a backup copy of the file before beginning, and the file should
be edited from a text editor such as Notepad. Editing of prefs.js is not
a procedure officially supported by Netscape, so do so at your own risk.
How to Modify the prefs.js File (Please Read First)
Before editing, close Communicator and make a backup of prefs.js, then
open the original in a text edit such as Notepad. To add a line, simply
type or copy it to a line of its own in the prefs.js file in the same fashion
as other options already in the file. Keep in mind that parameters in this
file are case sensitive (meaning that it does matter whether you
type an uppercase vs. a lowercase letter), and spelling and syntax errors
may cause the contents of the file to be deleted when you restart Netscape.
So be careful and back up everything first.
This page documents preferences that can be set in prefs.js, but cannot
be set from within the Edit | Preferences menu in the Communicator graphical
user interface. The basic structure of a prefs.js entry is as follows:
user_pref("browser.cache.directory", "C:\\Netscape\\Cache");
In the above entry, browser.cache.directory is the parameter,
and C:\\Netscape\\Cache is the value. Note that parameters are always
enclosed in quotes. Values are enclosed in quotes when alphanumeric (containing
letters or letters and numbers), however numeric-only values and true/false
values are not enclosed in quotes. For example:
user_pref("browser.cache.directory", "C:\\Netscape\\Cache"); (alphanumeric
value)
user_pref("browser.link_expiration", 10); (numeric value)
user_pref("browser.wfe.ignore_def_check", true); (true/false value)
Also remember that JavaScript is case-sensitive (it matters whether
something is in uppercase or lowercase), and as a result so is prefs.js.
An error in the case of a letter is equal to a spelling mistake. You must
also be careful to include all punctuation, such as parentheses, commas,
semicolons, and quotes. If you set a value equivalent to the Communicator
default value, the line will be removed when you start Communicator.
When you are done modifying the file, save changes then open Communicator
to test your new settings. If you have multiple user profiles, changes
must be made to each user profile's prefs.js in order to implement the
changes for all users.
Browser Settings -- Mail
and News Settings -- Java Settings --
Other Options
Browser Settings
Maximum Number of Simultaneous Connections
The maximum number of concurrent HTTP connections to a web server. Increasing
the value will only speed page loading if there is sufficient bandwidth
as available bandwidth is divided among the connections, and decreasing
the value may degrade performance. Default is 4 (fine for most modem users),
minimum is 1. There is no maximum, but there is a limit of 6 open connections
per browser window.
user_pref("network.max_connections", 6);
Network TCP Buffer Size
The amount of RAM (in bytes) to use for the TCP buffer. Larger values mean
more data but can saturate the system on faster networks. Default is 10240
(10K) and is also the minimum, maximum is 31744 (31K). Values outside the limits
will be taken to mean whatever limit is closest; i.e. 65536 will be taken
to mean 31744.
user_pref("network.tcpbufsize", 31744);
Network TCP Timeout
The time, in seconds, before a timeout error appears when attempting to
contact a server or perform a DNS lookup. This value should not be changed
unless the user is experiencing frequent timeout errors (if this is the
case, network maintenance is probably needed). A value of 0 for this parameter
will use the default.
user_pref("network.tcptimeout", 120);
DNS Cache Expiration Time
The time, in seconds, before a server's IP address is purged from local
memory. Subsequent requests to the server will require another lookup against
the DNS server. The default value is 900 seconds. Unless there is a specific
need to change this preference, it should remain the default value - reducing
the value may negatively impact performance and increasing the value may
cause problems against server farms.
user_pref("network.dnsCacheExpiration", 1000);
Disable Automatic URL Completion
Disables automatic URL completion ("AutoComplete") when typing in the browser
location toolbar. Remove the line below to restore the feature.
user_pref("network.enableUrlMatch", false);
Specify a Custom Bookmark File Location
Allows the user profile's bookmark file to be located anywhere on the hard
drive or network drive rather than in its default location in the user
profile directory. The Communicator bookmark filename is bookmark.htm.
Note the double-backslashes in the path example below - use \\ where you
would normally use \ in the path. (This feature is available in the GUI
in 4.02 and up.)
user_pref("browser.bookmark_location", "C:\\Netscape\\bookmark.htm");
Disable HTTP_REFERER Headers
Disables the HTTP_REFERER header sent to the destination web server when
you click a link. Be aware that disabling this header may cause failures
in some scripts and pages requiring authentication partly dependent on
this header. Remove the line below to reenable the header.
user_pref("network.sendRefererHeader", false);
Disable Asynchronous DNS
Disables browser use of asynchronous DNS. Disabling this feature may negatively
impact performance and users should only disable this if so instructed
by a system administrator or are troubleshooting winsock problems. Remove
the lines below to reenable Asynch DNS.
user_pref("network.use_async_dns", false);
user_pref("network.wfe.use_async_dns", false);
Cache HTML Pages Accessed via SSL
Allows HTML pages accessed over secure (SSL) HTTP connections to be stored
in the local disk cache. While this may aid performance as the pages can
be stored locally, enabling local SSL page caching can represent a security
risk since the secure pages linger on the local system. The default for
this is to not allow local SSL page caching, and to disallow it again,
remove the line below.
user_pref("browser.cache.disk_cache_ssl", true);
Show Images After Loading
Forces the browser to load the entire image before displaying it in the
window. Remove the line below to allow images to display while loading
once again. Note that this parameter may not work in all configurations.
A setting of false is not recommended on modem connections.
user_pref("browser.display_while_loading", false);
Check to See if Default Browser on Startup
Forces Communicator to determine whether it is the default browser on startup.
user_pref("browser.wfe.ignore_def_check", false);
Modify the Default Search Engine
Changes the default search engine called when you type ?{search keyword}
on the location toolbar. Note that this does not affect the Search button
on the main navigation toolbar. The target URL should complete a form submission
- for example, the AltaVista URL is http://www.altavista.digital.com/cgi-bin/query?pg=q&what=web&q=
where the value for q will be filled in by whatever text follows the ?
input by the user on the location toolbar. The default value for this parameter
is http://cgi.netscape.com/cgi-bin/url_search.cgi?search= which will randomly
select a search engine for the value of ? on the toolbar.
user_pref("network.search.url", "http://search.yahoo.com/bin/search?p=");
Options for Sorting Server Directory Listings
Controls the sorting of server directories, such as FTP directories. Default
is 0 (display alphabetically), 1 is sort by file type, 2 is by file size,
3 is by date.
user_pref("network.file_sort_method", 3);
Mail and News Settings
Reply on Bottom
(Communicator 4.02 and up only) Allows you to by default reply after quoted
text. Default is 1 (reply on top), 0 is reply on bottom.
To set it to reply on the bottom, cut and paste the pref below into
your prefs.js file. Backup the file "Before" editing !!!
user_pref("mailnews.reply_on_top", 0);
Add Extra Lines after Quoted Text
(Communicator 4.02 and up only) Allows you to specify an amount of extra
lines to add after quoted material. The value is the number of lines to
add.
user_pref("mailnews.reply_with_extra_lines", 2);
Control Movement Across Multiple Mail Folders and Newsgroups
(Communicator 4.02 and up only) Controls the behavior when the user clicks
the 'Next' button to go to the next mail folder or newsgroup containing
unread messages. Default is 1 (ask for user confirmation). 0 will cross
folders without asking and 2 will restrict the Next button to the current
folder or group (so it cannot be used to go to the next folder or group
containing unread messages).
user_pref("mailnews.nav_crosses_folders", 1);
Use MS Word Custom Dictionary
(Communicator 4.04 and up only) Allows sharing of the MS Word custom dictionary
to augment Communicator's spell checker. The value is the full path to
the dictionary (the filename is custom.dic and is found in the Office
directory). Adjust the path below as necessary for your system.
user_pref("SpellChecker.PersonalDictionary", "C:\\Office\\custom.dic");
Use X-Sender Mail/News Header
Adds a X-Sender header to outgoing messages. If authenticated SMTP is not
used, Unverified will appear after the user's e-mail address. Default value
is false. An example X-Sender header is: X-Sender: "Moi" <moi@myisp.net>
(Unverified)
user_pref("mail.use_x_sender", true);
Specify a Custom Address Book Location
Allows the user profile's address book file to be located anywhere on the
hard drive or network drive rather than in its default location in the
user profile directory. The Communicator address book filename is abook.nab.
Note the double-backslashes in the path example below - use \\ where you
would normally use \ in the path.
user_pref("ldap_1.directory1.filename", "C:\\Program Files\\Netscape\\Users\\your_profile\\abook.nab");
MIME-Encode 8-bit Headers
Always encodes 8-bit headers (separate from encode 8-bit characters in
the GUI). Use strongly discouraged except where necessary.
user_pref("mail.strictly_mime_headers", true);
Disable JavaScript in Mail and News
Disables interpretation of the JavaScript language in the Collabra (news)
and Messenger (mail) components of Communicator. JavaScript will remain
available to the web browser unless JavaScript is globally disabled in
Edit | Preferences | Advanced in the GUI preferences. Remove the below
line and be sure JavaScript is enabled in preferences to restore full JavaScript
functionality.
user_pref("javascript.allow.mailnews", false);
Disable Address Book LDAP Capabilities
Disables LDAP (Lightweight Directory Access Protocol) features in the address
book. Remove the line to restore functionality.
user_pref("mail.addr_book.ldap.disabled", true);
Send Charset Data to Server for IMAP Searches
Allows character set data to be sent to the IMAP server for a search. Only
needed in limited international use where the IMAP server also supports
this functionality.
user_pref("mailnews.force_ascii_search", false);
Disable Registry Lookup of Unknown MIME Types
When a message is encountered containing a MIME type that Communicator
does not know how to handle, it will fall back on the Windows 95/NT registry
to determine a default action for the MIME type. This will disable that
lookup in mail and news. Remove the line to restore functionality.
user_pref("mailnews.autolookup_unknown_mime_types", false);
Add HTML Domains to Address Book
Adds domains to the list in Edit | HTML Domains in the Address Book. All
recipients in these domains are considered to have a mail/news reader capable
of reading HTML. Add additional domains as demonstrated below (Communicator
defaults to the netscape.com and mcom.com domains).
user_pref("mail.htmldomains", "netscape.com,mcom.com,foo.com");
Java Settings
Disable Security for Unsigned Applets
Disables Java security for applets. WARNING: Since this parameter
completely disables Java security, it should be only used for local applet
testing and should never be used over a network and the Internet. Remove
the line to restore Java security.
user_pref("signed.applets.codebase_principal_support", true);
Lock Java User Capabilities Database
Prevents users from adding additional functionality to the capabilities
database (signed.db) such as by accepting signed applets from the Internet.
If needed in a controlled environment, it is recommended that Mission
Control be used to lock this preference.
user_pref("signed.applets.capabilitiesDB.lock_to_current", true);
Simulate Navigator 3.0x Behavior for Local Classes
Allows local classes in the classpath to have special privileges such as
universal network connections and the ability to load Dynamic Link Libraries.
Access to the file system is not permitted with this option - the Capabilities
API must be used instead.
user_pref("signed.applets.local_classes_have_30_powers", true);
More information on Communicator Java options can be found in the Security
Preferences Documentation.
Other Options and Locking Preferences
Please note that the above options can be set by any user able to modify
prefs.js. If you operate in an environment that requires preferences to
be locked in a certain state, you should consider Mission
Control, which allows you to lock both GUI preferences and those above
plus several others. Mission Control also allows you to universally set
and/or lock preferences in all users' Communicators, eliminating the need
to modify each and every prefs.js.
Command Line Options are detailed in the Netscape
Support Knowledge Base. An additional command line switch, -start_java,
is not mentioned on that page but can be used to preload the Java subsystem
when starting Communicator.
Netscape also has a number of undocumented functions, some useful, some
fun. The following keystrokes are available in the browser window:
CTRL-ALT-T Show the current state of HTTP connections (monitor
progress of a loading page at protocol level).
CTRL-ALT-S Hide/Show the browser status bar.
CTRL-ALT-F Go to the Fishcam.
Additionally there are a number of about: functions which are mainly
internal URLs (such as about:, about:javalogo,
and about:license) while others link to developers'
pages or are Easter Eggs (such as about:mozilla).
The Netscape Tricks and Easter
Eggs page is one of several that provide more information on other
about: functions.
Other options, such as HTTP_USER_AGENT/X-Mailer header customization,
logo image ("throbber") alteration, additions to dropdown buttons, and
"about text" are only available in Mission Control and cannot be set from
the prefs.js file.
Kevin Hecht
Visit
the Main UFAQ Page
for other Tips, Tricks and Setup Examples
This page is maintained by Frank Tabor, Jay Garcia and Kevin Hecht
and
This material is being made available to you subject to some
Legal Stuff
This page was created with the Netscape Communicator Composer
Last Updated: Fri Nov 28 17:23:57 1997