IGPS-Info on Java and other animations used in these pages

This page uses Netscape 2.0x/3.0 features

Java | Java Script | animated GIFs

You do not see any animation? Pity, your browser is not Java-compatible! Check out below.

Can you run Java?

General: Platform independent Java-language is a promising new net feature but appears still in an early stage of development. We use some Java-applets for testing purpose for the IGPS-pages, which should run if you use a compatible browser, e.g. Netscape Navigator, 2.0 or higher, or Sun's Hot Java Browser.

Note for Mac-users: Unfortunately, the released Navigator 2.0x for Mac versions do not support Java. For Mac Power PC you need to use Navigator 3.0.
New: Navigator 3.0 also supports Java on Mac 68xxx platforms (at last, because I work on Mac68040 at home and on MacPPC at work), although there are still some problems in this version (see below). Hot Java does not yet support any Mac platform but releases are announced.

I do not know about the compatibility of Java with Microsoft Explorer. Probably, the Windows 95 version supports Java, but how about the Mac-version?

Java-challenged browsers: If you use another browser, Java animations (applets) will not run but in most cases an alternative text or image will be displayed, including the note that your browser is 'Java-challenged'. If you see this note despite using the Java-compatible software, make sure that you enabled Java-language in the preferences menu of your browser.


General problems: Depending on computer configuration, some applets appear to be loaded (provided you use a Java-compatible browser) but don't run and you might not even see the alternative non-Java-display. To my present knowledge, all applets used here should run on MacPCC and Unix systems, but seem to have problems on some Windows-configuration. There are some known Java-bugs which are not fixed yet: Many audio- and text applications only run under 256 colours (I did not use these).
Remote Java-applets cannot be executed when you are surrounded by a stringent Firewall.

Problems with Mac68xxx platforms. Navigator 3.0 is the first browser which supports Java on Mac68xxx platforms. However, I noticed that not all text applets run and some other applets might not not run smoothly. This will hopefully be fixed in a future release of Navigator 3.0.

Memory problems: Some applets also might not run if your system is low in RAM. Provide your browser with as much memory as possible.
Java and Java-Script (see below) are memory consuming, so if your browser suddenly runs very slow or sometimes even crashes, you better disable Java and Java-script (for Navigator: Option/Network Preferences/Languages Settings). On my Mac68xxx home computer which runs with 8 kb RAM (+ 8kb virtual memory) only, I still use Java and Java-script, but I have to apply a memory cleaning utility (e.g. shareware MacPurge) whenever Navigator tells me that it runs out of memory (I have to quit Navigator before applying this). Any better suggestions are welcome (of course enlarging RAM will be the best solution).

Java-test: You should see a Java-applet (animated, very nervous text) on this document just below the headline of this page. Does it run on your platform? Letters should hop around (rather than repeating the entire text string, as it may happen under Navigator 3.0b4 on Mac68xxx if you have loaded other applets before). Additionally, do you get the sound applet just below this paragraph? Just touch it with the pointer!

You cannot try this applet because your browser is not Java-compatible!

Feedback: If you have a Java-compatible browser but our animated applets, or some of them, do not run, please INFORM ME (by including your computer-specification: Operating system, chip type, RAM-size, browser software, number of colours). We'll pass these informations to the Java-developers at SUN or to Netscape. I would also appreciate a note if all applets run smoothly on your system. Thank you for your support!

Examples of Java-applets on these pages:

Find out more about Java at Sun's Java Site.

How about Java-Script?

If the annoying alert welcoming you as a Java-Script-User popped up whilst loading this page, your browser is Java-Script enabled. Java-Script (earlier called Live Script) is a scripting language where the source code can be directly added to html-documents. Netscape Navigator (2.0x or higher; including Mac-versions) and (I believe) Microsoft Explorer is able to execute these scripts. If you use one of these browsers, you should see this page fading in (- just try again with the reload button -) and an alert should pop up both while loading the page or when you touch HERE with your pointer. If you disabled Java-script or use another browser the background of this page will be grey. For more infos go to Netscape's homepage

Note that there is a certain discussion as to the security of Java and (especially) Java-script.
Actually, Java-script can ask your computer questions and can even store information on your harddisk in a file called Magic Cookie. However, this information can only be read by your browser software but not by any remote web server. Here is an example:

Hello, your browser / operating system is !

You may reload this page to see the text above updated.

If you are nevertheless concerned about security or if you get error messages when running applets you may disable both Java and Java-Script in the Preference Menu of Netscape Navigator.

Examples of Java-scripts on these pages:

Find out more about Java-Script at Netscape's site.

Animated GIF-Images

You have disabled both Java and Java-script but still see some animated images in our pages? These are no cgi-governed animations but simple GIF-Animations. They are a good alternative to some Java-animations although they have limited capabilities (only stacked images can be played, similar to a short movie, however without sound).


Find out more about animated GIFS. Thanks to Gerd Marstedt, Bremen, for the hint.

Anything still wrong with these pages? Contact Reinhold Leinfelder.

I promise, this is the last Java-Script example here:

You have been at this page for

Maybe it is time to collect your reward!

Last changes 8. October 1996 by Reinhold Leinfelder

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