Arena Frequently Asked Questions

This FAQ originates from W3C Arena FAQ created by Håkon Lie.

Arena style sheets do not seem to work as specified?
Arena's support for style sheets has not been keeping up with the specification, and we encourage you to fix this situation with CSS1 specifications.

Why was Arena originally developed?
Arena's original purpose was to be a testbed for new features of the web. In the past, W3C has used Arena to implement HTML3 features including tables and math, style sheets and new graphics formats such as PNG. Also, Arena was a testing tool for the W3C Reference Library. Now Arena development has been taken over by Yggdrasil and the free software community with the aim of developing a full-featured free web browser that will provide a superior alternative to proprietary browsers.

What is a style sheet?
HTML was not designed to give authors control over the final presentation of a document. Fonts, color and volume has been the domain of the reader/browser. Many authors want to influence the final presentation, and many readers would like them to. Style sheets provide a way to attache presentation hints to the documents without affecting HTML. This is a much debated issue, and you may want to read more of the background material available. You may wish to have a look at a sample web page with style sheets.

What is HTML3? HTML 3.2?
See the W3C resource page on Markup for more on this.

How do I specify colors in the style sheet mechanism?
You can either specify colors in hexadecimal RGB values (both 3 and 6 a character are accepted, e.g. #F0F, or #FF00FF), or using names that your window system (i.e. X11) knows.

Using the new style sheet mechanism I don't seem to be able to control the colors accurately, why?
The style sheet mechanism does not allocate any new colors, but reuses the ones found in the dithering cube. Arena will give you the best approximation available.

How do the style sheets cascade?
The style sheet found in your initial document becomes your personal preferences. It will be applied to other pages, unless the other page has its own style sheet. If so, the two styles will be merged with preferences given to the latter document. Extra weights can be added with the "!important" construct. See the CSS specification for more on this.

Why isn't Arena available for my flavor of unix?
When releasing a new version of Arena, W3C compiled for the platforms that are easily available (sunos, solaris, Linux, sgi). Unfortunately, several popular platforms were not represented there. W3C therefore made source code available for porting, and could point to binaries that others had compiled.

Yggdrasil does not provide any precompiled binaries yet. Although volunteers are encouraged to do this. If you compile Arena for your platform and want to provide it to the Internet community you are welcome. Please, send email about the binary availability and location to the arena-developers mailing list or to the Arena Project Coordinator and we shall place the hyperlink to the Arena web pages.

How do I prevent Arena from going to each time it starts?
Unless instructed otherwise, Arena will fetch the relevant release page from the Yggdrasil server. It is a useful page (that you also can reach through the "Help" button), but you may not want to do this every time. Either start arena with a URL as an argument (e.g. arena, or set the environment variable WWW_HOME to a URL (in csh: setenv WWW_HOME

How do I convert LaTeX math symbols and tables to HTML3?

How can I make HTML3 <MATH> element start with superscripts or subscripts?
One should place the base inside the <math> element as well. If the font of the base is not correct, you can control it with <t>, <b> and <bt> elements.

Example: <math><t>base</t><sup>super</sup></math> is rendered as basesuper.

What does the "Bad HTML" message in Arena mean?
If Arena finds HTML errors in the document, he flags it in the upper right corner. (The number in parenthesis is an internal error code, not line number or number of bugs.) In most cases, Arena and other browsers will still be able to show the document as intended by the author, but who wants to be seen in cyberspace with a bad HTML flag?

How can I see HTML errors?
If you want to see --- and fix --- the errors, press the "Edit" button. Arena will start the editor specified in the EDITOR environment variable (or using the "-editor <editor>" option). The raw HTML will be inserted in the buffer along with short error messages camouflaged as comments. You can set the maximum number of errors to be flagged using the -badflags option.

After you have been through an edit cycle, you will also see the errors when toggling the view button.

How can I edit HTML in Arena?
Start the editor as described above. Make your changes, save the buffer, exit the editor, and Arena will show you the edited document. To save the file, either press the "SaveAs.." button and type in a file name (no expansions are supported yet), or go into your editor and save the buffer into the proper filename from there.

What are the command line options?
Please see the documentation or

How do I run Arena from behind a firewall? Has it been SOCKSified?
Arena is not SOCKSified, but the CERN httpd proxy server is. Therefore, you can get through your firewall by pointing Arena to a proxy server running on the inside.

How does Arena cache documents?
Currently Arena does cache in memory and also uses disk for this. By default, Arena will write fetched documents into /tmp (or whatever set in TMPDIR environment variable). E.g. http document from CERN's info server will go to /tmp/Arena.cache/... and it's URL hash will be placed to to index file /tmp/Arena.cache/.index. When exiting, Arena will flush all memory cached documents and the corresponding structure to the disk persistent cache. This behaviour is default to libwww-5.0a.

Also, if you run several Arena processes simultaneously on the same machine you may want to specify different cache directories as they will not be able to take advantage of each other's caches. See command line options.

What X11 resources can be set?
W3C is moving away from the platform-specific X11 resources toward style sheets that are platform independent. For more on how to write a style sheet, see the specification. Note that the syntax has changed over time, so make sure you have the latest version of Arena. If you use an earlier version, see the style sheet examples under the help page.

Yggdrasil is going to support X11 resources as a fall-back technique (when no user style sheet is found).

What hot-keys does Arena support? Why not <space>?
Arrow keys will move you around in the current document. Ctrl + arrow keys will do page up/down and forward/backward in history (fvwm? :( ). Also, the following X11 keys are supported: Page Up (XK_Prior), Page Down (XK_Next), Home (XK_Begin) and End (XK_Home).

W3C has not been supporting some of the other common hot-keys (e.g. <space> for Page Down) because this could conflict with future HTML editing. Enough people had asked for this to make them reconsider.

Why doesn't index searching, hot-lists --- or other features --- work?
W3C answer:
Arena's primary purpose is to be a testbed browser. These things have been done before, so they're not that exciting.

we are going to implement all these features and support a number of new ones.

How can I specify external viewers?
Arena supports mailcap files. If you have a file called .mailcap in your home directory with this line in it:
image/gif; xv %s; quality=0.95
Arena will display all images using the xv program instead of inline. The quality statement is an indicator of how well the application is able to display the data type. The HTTP server may use this information to determine what format to send to you. The default quality is 0.5.

Arena will also look for other mailcap files that the MAILCAPS environment variable points to.

Help! Arena displays all images externally. What's wrong?
You have probably declared an external viewer for GIF images. Arena does not distinguish between inline and "outline" images; if a viewer is defined, it will be used for all images.

How can I make Arena work with proxies?
Arena (i.e. the library) reads the http_proxy environment variable. Using csh, you could say
setenv http_proxy
This is also described in the CERN httpd documentation.

On my sun, Arena can't find any hosts. What's the problem?
Name resolving. W3C had answered: Try using "the other" binary, e.g. arena-sun4-4.1.1-lresolv.bin or arena-sun4-4.1.1.bin. But this advise is outdated. Now we answer:
If something doesn't work, fix it!

Arena comes up in black and white (or grayscale) on my color screen. Help!
There is probably another application hogging the colors. Try quitting other applications (e.g. Netscape and Mosaic) and restart Arena. Or, you can start Arena with the "-cm" command line option (introduced in 0,98).

I submitted a bug report, but it still isn't fixed. Why?
We do try to answer all bug reports.

If you have a paid technical support contract with Yggdrasil, try submitting your problem to, which is handled by a staff completely separate from Arena development.

If you do not want to use Yggdrasil technical support, we will still eventually work on the problem you have submitted, but, if you are in a hurry, consider finding and fixing the problem yourself and then submitting a patch. Remember, Arena development is now covered by the GNU General Public License, so your contributions benefit the entire free software community.

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