Tips and tricks for Netscape® Navigator for Windows95 and 98

General information

In the text below you will find terms like Navigator and Communicator. Unless indicated otherwise each of them refers to both versions (i.e. both standalone Navigator and browser part of Communicator). The only difference is in enabling external mail client, as communicator comes integrated with mail and news clients, whereas Navigator is a standalone application.

Several procedures described below involve editing of a file prefs.js, located in the ...\Netscape\Navigator\Users\{username}\ directory. The file is crucial to the software. Before editing this file make sure that all windows of Navigator are closed (otherwise the changes may be overwritten, or program may crash). The file must be edited in a text or ascii editor (such as Windows' Notepad), do not use a wordprocessor as they add special formatting characters or even (like Word 97) save the file in a binary format that would make the file totally unrecognizable. Of course you can use Word and save the file in a text format, but it is definitely an overkill. Before opening the file for editing make a copy of it, or you may be faced with a perspective of reinstallation. You have been warned. IMPORTANT NOTE: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):

As mentioned above, before editing close Navigator and make a backup of prefs.js, then open the original in a text editor 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. To change some settings you just change an existing line (value after an equal sign, taken into double quotation marks). 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. Also remember that Navigator may delete some lines set for program's defaults (so don't be surprised if this happens to you - it is perfectly normal).

The procedures come from an unofficial Netscape Navigator/Communicator FAQ site, UFAQ, my experiments and some scattered internet sites. They have been tested by me (unless indicated otherwise), but come with no warranty whatsoever - any changes you do at your own risk.

Installation files

It is possible to decode Windows' version of Navigator or Communicator from the installation file's name:



aa - signifies package contents (n - navigator standalone (highest version to date is 4.08), cb - communicator basic, cc - communicator complete, cp - communicator professional i.e. compete plus calendaring, g - navigator gold (versions 3.x and below) )

xx - signifies platform (16 or 32 bit)

b - signifies encryption (d means domestic grade 128 bit and e means export grade 40 or 56 bit)

yy - signifies version. Depending on version this block can be two or three digits long (e.g. 461 means version 4.61 and 47 means version 4.7)

so for example installation file named
cb32e47.exe means Communicator Basic, for 32-bit platforms (Win 9x, NT4 and Win 2000), with export-grade encryption strength, version 4.7; and n32d408.exe means Navigator (browser only), for 32-bit platforms, 128-bit encryption (that can be used by US and Canadian residents only), version 4.08. Armed with this knowledge one can now search for appropriate installation package on a server giving fastest download.

How to configure Netscape® Navigator to work with other mail programs?


In Navigator versions 4.03 and above, you can configure Navigator to invoke external MAPI mail clients such as Eudora or Outlook, or other mail clients that understand the Simple MAPI protocol. Navigator does not support any MAPI commands outside the Simple MAPI protocol. While this has been tested with the Microsoft Exchange 5.0 client (not by me) and Pegasus Mail 3.11, it has not been tested with any more recent versions and may not be compatible.

This procedure only works for Microsoft Windows 95, 98, and NT for standalone Navigator. It will also work for Communicator as long as you put a file called navmapi32.dll into ...\Communicator\Program folder (I didn't check it - only read it on the newsgroup for Pegasus Mail users). This solution will also stop Communicator's own mail client responding to clicks on e-mail links.

Enabling the Third-Party Mail Client

To enable third-party client functionality in Microsoft Windows, you must configure the Netscape Navigator preferences file, prefs.js, which by default is located at C:\Program Files\Netscape\Users\Default\prefs.js.

In this file, you must set the following four preferences. The first sets the intention to use third-party mail to True, the second tells Navigator to run its own news client after clicking on news: link, the third names the MAPI DLL to use . Open the prefs.js file in a text editor such as Notepad and add the following lines to the bottom of the file:

user_pref("mail.use_altmail", true);
user_pref("mail.use_altmail_for_news", false);
user_pref("mail.altmail_dll", "navmapi32.dll");

Note: Be sure that your mail program is configured as your default MAPI client.

Navigator 4.03 and higher ship with a file called navmapi32.dll. This DLL allows use of Simple MAPI compliant 3rd party mail programs (i.e. Eudora, Outlook, etc.) with Navigator. The default location of this file is C:\Program Files\Netscape\Program\navmapi32.dll. If you wish, you can write your own DLL using the Navigator Third Party Mail and News SDK available on and use it instead of the provided DLL. Once you have written your DLL, substitute the name of your DLL for navmapi32.dll. Note that if you set mail.use_altmail to "true", you must set the mail.altmail_dll preference. Otherwise, third-party mail handling defaults to navmapi32.dll.

Using a MAPI mail client

Once you have configured Navigator to use a third party MAPI client, you can open a message composition window provided by the client in one of these two ways. In Navigator:

How to enter a different e-mail addresses for mail and news?

It is common that when posting to the newsgroups the real return address is not given in the header. This measure can drastically cut amount of spam being sent to our e-mail address. This is not necessary (and is considered to be against netiquette) for e-mail - as details from our e-mail messages normally are not available to third parties such as e-mail address harvesters. Unfortunately the Netscape Communicator does not allow to enter different addresses for e-mail and news postings. To overcome this deficiency go to Desiderata Software site and download their FixNews add-on. It will enable to enter a different return e-mail address for news postings and will add some extra filtering (including killfile) capabilities. The program in version 2.0 is freeware.

How to disable/enable default browser check?

When the program is started, by default it checks if it is a default browser and if it is not, it asks if you want it to become your default browser. This feature can be turned off by the following line in prefs.js:

user_pref("browser.wfe.ignore_def_check", true);

by changing true to false (or deleting the whole line completely) Navigator will again start checking if it is the default browser on every start. If you set it to false, this line will be then deleted when Navigator is started next time.

Speeding up Navigator: loading Java virtual machine at Navigator's start

Normally navigator only loads Java machine when it encounters a page with Java, and unloads Java machine as soon as the page is left. When browsing pages with Java it pays to start Navigator and Java together using the following command line:

"C:\Program Files\Netscape\Navigator\Program\netscape.exe" -start_java

(edit properties of the shortcut that you use to start Navigator to implement this command line). This way Java machine is already loaded when Navigator loads a page with Java and after leaving the site Java virtual machine remains loaded.

Changing which plugin will be used to play certain embedded files

When several plug-ins handle the same mime type, one of them will get priority over that mime type.

The Windows-based versions of Netscape Navigator and Netscape Communicator will load plug-ins based on the order they occur in the \Plugins directory. The first item to occur in the directory will load first, making it the lowest priority, the second item will be the second lowest priority, and so on. If the QuickTime plug-in occurs last, it will get priority over all of the mime types it can open. You can use the "DIR" command from a DOS command prompt to determine the current directory order of the \Plugins directory. Do not use the order shown in Windows 95.

If you wish for another plug-in to open a given mime type, it must occur in the \Plugins directory after the QuickTime plug-in. Begin by moving the entire contents of the \Plugins directory to another directory. Moving only a portion of the plug-ins out and back into the \Plugins directory, or reinstalling plug-ins using an installer is not a reliable method for changing the loading order.

Using Netscape Communicator 4.05, this example shows how you might configure LiveUpdate's Crescendo to open .MID files, Netscape's plug-ins to open .AU, .AIF, .AVI, and .WAV files, and QuickTime to open .MOV files along with any other remaining mime types. Since QuickTime can open the same mime types as Netscape's plug-ins, and Crescendo, it must be loaded first (lower priority). Netscape's LiveAudio and Crescendo can both open MIDI mime types, therefore, Crescendo (higher priority) must be moved after LiveAudio (middle priority).

This procedure requires three basic basic steps.

  1. Exit Netscape.
  2. Move the entire contents of the ...Netscape\Communicator\Program\Plugins directory to a different directory.
  3. Move each of the plug-ins and its components back to the Netscape\Communicator\Program\Plugins directory, starting with the lowest priority, and ending with the highest.
It may be easier to print out a list of the installed plug-ins (use DIR {path}\plugins > {path1}\{filename}.txt and note which plug-ins can open the same mime types, then prioritize the noted plug-ins.

Here is the order for this example:

Plug-in   File Name Remarks
Netscape Default   npnul32.dll <- lowest priority (first moved)
QuickTime   npqtplugin.dll
Netscape Audio Streaming   nplau32.dll
Netscape Sound Player   npaudio.dll
Netscape AVI
Netscape AVI   npavi32.dll
LiveUpdate Crescendo   MPlayer (sub-directory)
LiveUpdate Crescendo   crestest.mid
LiveUpdate Crescendo   CresPlayer.class
LiveUpdate Crescendo   crestest.htm
LiveUpdate Crescendo   CresObserver.class
LiveUpdate Crescendo   DelsL1.isu
LiveUpdate Crescendo   Npmidi32.dll
LiveUpdate Crescendo   Sequence.dll
Cosmo Player   Cosmo (sub-directory)
Cosmo Player   npcosmop.jar
Cosmo Player   npcosmop.dll <- highest priority (last moved)

In the example above after encountering an embedded file Navigator will first check if Cosmo Player can render it; if not, will check if Crescendo can be used; then will try Netscape AVI; after it Netscape Audio Streaming; subsequently Quicktime; and will finish with trying to use Netscape Default plug-in. The process will be stopped on the first plug-in that is able to render the format in question.

Note: You can verify which plug-in is enabled for each mime type by choosing About Plug-ins from the Help menu.

If you would like more refined control over mime types and plug-ins, consider using one of the third party applications specifically designed to assign a mime type to a particular plug-in.

How to spell in other languages?

There are people who correspond in other languages or post to foreign-language newsgroups. It is very easy to add spell-checking capability in some other language: all that is necessary is to download appropriate file and put it into a ...\Netscape\Communicator\Program\SpellChk folder. Just make sure that composer is not running at that moment. The only problem is that there are just a few languages supported. The files have got rather cryptic names, but they always start with a "p", second and the third letter of their names signify language. They can be downloaded from here. Obviously it only works with Communicator,

Available languages are: Catalan (pca4s323.dat)
English (GB and US)
Portugese (European and Brasilian)


After typing "About:" followed by some keyword and pressing Enter, Navigator will show some information, more or less useful. Some of them no longer work in Navigator 4.08 and later versions of Communicator.

about: - information on Netscape version.
about:logo - Netscape logo.
about:license - Netscape license that you agreed to.
about:???logo - logo of a plug-in or module.
qtlogo (QuickTime), visilogo (visibroker for Java), tdlogo (Bitstream TrueDoc), odilogo (ObjectStore PSE for Java), mclogo (Marimba Castanet), ncclogo (Netcast), insologo (Inso Interantional Proofreader), fclogo (FullCircle Talkback software), logo (Netscape), javalogo (Java), rsalogo (RSA Data Security encryption)
about: followed by one of these: marca, ari, atotic, blythe, chouck, dmose, dp, ebina, hagan, jeff, jg, jsw, jwz, karlton, kipp, mlm, montulli, mtoy, paquin, robm, sharoni, terry, timm - to go to personal pages of NN creators. (some of them have since moved).
about:mozilla - a bible verse Netscape style.
about:cache; about:global; about:image-cache; about:memory-cache - information on the contents of your cache.
about:plugins - information about loaded plugins.
about:fonts - information about fonts.
about:Pics - changes title to XXXXXXXXXXX and cannot find file picsfail (it means that this about: no longer works).
about:security?banner-insecure - logo for unsecured page. Instead of insecure you can use: secure, mixed
about:authors - changes title to Mozilla über Alles and notifies that the page has been removed (it means that this about: no longer works).
about:document - page info for last visited page

Opening Javascript console:

Window - Java Console. Or type into open location box:

Viewing browsing history:

press Ctrl+H (or through menu: Window - History). Or type into location field: about:globalhistory.

To force a cache reload:

Hold down the 'Shift' Key (Option Key on Macintosh) while clicking on the 'Reload' button in the browser window. This forces Communicator to reload the page from the source rather than getting it from cache. But since reloading means reconnecting to the server, this can be a slow process. When you click the 'Reload' button, Communicator checks to see if the page has changed at all (on the Web Server). If it has not changed, Communicator reloads the page from the local cache. It only reloads the page if it is different from the one stored in the local cache.

How to install a downloaded update file (*.jar)?

The SmartUpdate files are in .jar format (java archive). Use Communicator to open them. There are two ways to do this:

  1. From the File menu, choose Open Page. Enter the path to the .jar file you just downloaded and click Open. Communicator will open the file and begin the SmartUpdate process.
  2. Drag and drop the .jar file on top of the Communicator window. It will open automatically. Then follow the on-screen prompts.

How to make Communicator prompt to disconnect DUN at shutdown?

Download the file AUTOCLOSE.ZIP (, unzip and then:

  1. Put the program Rasexit.exe in the C:\Windows\System folder.
  2. Double click on the file Autoclose.reg.
  3. Go to your C:\Windows\System folder and double click Rasexit.exe.
  4. Close Rasexit.exe.
  5. Reboot computer (May not be necessary).
Also: Verify that c:\windows or c:\windows\system contains MFC42.DLL and MSVCRT.DLL (available in the UFAQ Downloads Section and from many ftp servers and shareware repositories. UFAQ also makes these files (and many more) available here. )



user_pref Settings for the prefs.js Configuration File

This section 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("", "C:\\Netscape\\Cache");

In the above entry, is the parameter, and C:\\Netscape\\Cache is the value. Note that parameters are always enclosed in quotes.

font face="Times New Roman" size=3 color=#000000>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("", "C:\\Netscape\\Cache");

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

- 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);

- Maximum Number of Characters for Personal Toolbar Items: (Communicator 4.06 and up only) Controls the maximum number of letters an items on the browser's Personal Toolbar can contain before the item's name is truncated. The default is 15 characters.

user_pref("browser.personal_toolbar_button.max_chars", 25);

- Use the Guide Button Instead of the My Netscape Button: (Communicator 4.06 and up only) Communicator 4.06 and 4.5 introduce the My Netscape button on the Navigation Toolbar. If you prefer to use the old Guide button, insert the following line. Remove the line to bring back the My Netscape button.

user_pref("", true);

- 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 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 which will randomly select a search engine for the value of ? on the toolbar.

user_pref("", "");

- 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);

- Control Time Interval Between nsreg.dat Compactions: (Communicator 4.5b2 and up only) Controls the period of time between compression/updates of the Netscape Client Registry (...\WINDIR\nsreg.dat). The units for this preference are in days; the default is 60 days.

user_pref("autoupdate.regpack_interval", 30);

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.

Netscape's DevEdge site provides a nearly full list of Communicator preferences though it is not always kept current and mixes in preferences only available via Mission Control. You can get a full list of your own preference settings by going to a URL of about:config in the browser. Command Line Options are detailed on the Netscape Developer Site.

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.

A free but more limited customization tool, the Client Customization Kit, is also available from Netscape.

Keyboard shortcuts

Ctrl+A Selects all text on page (or Active frame) displayed
Ctrl+B Displays bookmarks window
Ctrl+C Copies highlighted text to clipboard
Ctrl+F Opens Find window (same as Windows command)
Ctrl+G Repeats last search (same as Windows' F3 key)
Ctrl+H Opens Browsing History window
Ctrl+I Opens window with page information (source URL, URLs of graphics and links, if any, and some info)
Ctrl+N Opens another Navigator window (allowing to browse simultaneously on more than one site)
Ctrl+O Opens a field where you can put a URL or addres of a file (it has got the same effect as writing it in the location field, but is not cached and doesn't show up in the drop-down list)
Ctrl+P Prints page (or active frame) displayed
Ctrl+Q Closes all Navigator windows
Ctrl+R Reloads page (same as Windows' F5 key)
Ctrl+S Saves currently displayed page (or active frame)
Ctrl+U Opens window with page source (the HTML code). It does not allow to edit it though.
Ctrl+W Closes this particular window of Netscape, other windows remain open
Ctrl+Z Undoes editing change done in an edit box
Ctrl+Home Scrolls frame to the top
CTRL+ALT+F Go to the Fishcam
CTRL+ALT+S Hide/Show the browser status bar. (after the change described elsewhere: CTRL+ALT+I)
CTRL+ALT+T Show the current state of HTTP connections (monitor progress of a loading page at protocol level)
Ctrl+End Scrolls frame to the bottom
Spacebar Scrolls one page down
PageDown Scrolls one page down
backspace Scrolls one page up
PageUp Scrolls one page up
F1 opens Netscape's Help
F3 Repeats last search (same as Ctrl+G)
F6 Toggles all open Navigator windows
Alt+Left Arrow Back
Alt+Right Arrow Forward

How to replace combination Ctrl+Alt+S:

Some languages have a letter s with a diacritical mark. In some keyboard layouts this letter is inserted by a combination AltGr+s. Unfortunately, Netscape interprets it as Ctrl+Alt+s and hence it is not possible to write this letter. Below is given a step-by-step instruction on how to correct it:

  1. open the file resdll.dll (if you followed installation defaults the file is in the folder ...\Communicator\Program or ...\Navigator\Program) in a hexadecimal editor.
  2. find the following byte string:
    1B 00 53 00 01 E8
    and replace it with this one:
    1B 00 49 00 01 E8

Legal 128-bit encryption for users living outside of North America and not wishing to upgrade their Netscape software

Fortify makes available upgrade for export-grade Navigator and Communicator (versions pre-4.7) that brings it up to the same security level as the US products. Just think of safely charging all these purchases you always wanted to make over the internet to your credit card without sending extra letters or PGP-coded e-mails, everything just from the order page! Since the US government relaxed restrictions on exporting the encryption technology it is possible to download and install package with the same 128-bit encryption technology that only those living in North America used to be able to, but many users are perfectly satisfied with their existing Netscape software and see no reason to go through the pains of downloading hefty installation file and upgrading - then this upgrade is for them. It gives the same 128-bit security as the so-called "domestic" version and is available in English and German, Italian, Swedish, Polish, Russian, Mexican-Spanish. And it is free for all private and non-commercial use! It is a must-have for all those that buy online and pay by credit card on a per-transaction basis - especially that it is now possible to crack a 40-bit and 56-bit security code (the so-called "export strength") on a network of common-or-garden variety PCs in about one day (40-bit) or less than two days (56-bit) - well, in order to achieve these impessive results it was necessary to network some 100,000 PCs over the Internet, and it is hardly possible that lowly credit card number thieves will resort to such an extravagant and costly way to get somebody's CC number, but it at least gives an idea of a degree of vulnerability of the export-strength security. Supposedly NSA can break the 56-bit encryption in less than a minute; at present even if all the PCs worldwide were networked and given to the task of breaking a 128-bit encrypted transmission it would take millenia.

The US government relaxed its laws concerning export of advanced technologies and as a result of this it is now possible to download browser with 128-bit encryption for nearly everyone. Current version 4.75 is available only with 128-bit encryption.

This upgrade has not been implemented by me - I use a browser with 128-bit security already built in - so I can make no comments on it.

Prepared and compiled by Marcin Frankowski