More advice for the full screen mode.
Sivut toimivat riittävän hyvin MS IE 4.0+, Opera 5.x+, Netscape 6.0+/ vast. Mozilla ja Konqueror 3.x selaimilla. Yleisesti ottaen sivut toimivat parhaiten uusimmilla Opera selaimilla. Sivujen toimivuus vanhemmissa selaimissa on heikko, erityisesti Netscape 4.x kohdalla.

I list below all topic groups, which I have done according to subjects, which they handle. You can return to this topic group by using this menu and the link Table of topic groups on the top of the each page.



UA CSS in Mozilla Gecko browsers

Browsers after Netscape 4.x have much UA CSS. In concerns both the interface and the presentation of documents. Netscape (and evaluation version of it like Mozilla) are in my mind first browsers, which use UA CSS at the way, which is explained in the CSS2 specification - defining the default presentation of (X)HTML elements. Default setting are stored in /res/html.css, /res/forms.css and /res/quirk.css CSS-files (/ = the base directory of Netsape/Mozilla).

The used CSS is primary standard CSS2. In my mind the most inconvenient feature in the UA CSS files is, that part of the UA CSS is defined by using the keyword !important. Then Web-authors can wonder, why some defined CSS don't work. Below is a piece of code from the file html.css:

frameset {
display: block ! important;
overflow: hidden;
iframe {
background-color: transparent ! important; /* (b=49779) */
border: 2px inset;

What kind of non-standard (proprietary) CSS browsers support in UA CSS files is absolutely ok, because it is for the internal usage of the browser. But "teasing" authors by using the keyword !important is in my mind inappropriate. It can't be assumed, that authors could understand to use the same keyword to override default settings, which are defined in UA CSS files!. In addition there is a small inconvenient feature in the UA CSS. Some standard CSS2 property values to the element LI are defined so, that default property values of that element are different as W3C has been recommend.

Indeed concerning the /res/quirk.css the usage of the important rule is ok, because the purpose is to emulate with certain DTD the buggy behaviors of the Netscape 4.x series. In this case is also correct to use proprietary CSS in order to cause non-standard behaviors.

The existence of UA CSS and proper usage of it could be possible mentioned? I don't have found information about the UA CSS, which new Netscape/Mozilla browsers use.


UA CSS in Opera 4.x+ browsers

Like Netscape/Mozilla Opera 4.x+ doesn't use an external UA CSS file in order to define the default settings of (X)HTML elements. Indeed according to an e-mail Opera does have a default UA CSS-file, which is built into the browser, but not available as an external UA CSS-file in some folder of Opera.

Instead it use external CSS-files in order to define default settings for other other file types and special implementations like rendering WML 1.x documents. UA CSS files are stored in Opera 5.1x to the sub-folder Styles (in Opera 4.x in the root directory of Opera). Concerning WML the purpose of What kind of non-standard (proprietary) CSS browsers support is to define the presentation of the element card by using position:deck, make linking to work and show used images (the property -replace()). To use proprietary CSS for this purpose is fully acceptable.

I have written a letter to Opera Software because it doesn't inform, that the proprietary CSS is especially designed as UA CSS. According to the Web-site of Opera Software the What kind of non-standard (proprietary) CSS browsers support: can be used - even if it is not recommendable - to use in XML-documents to get linking to work. (concerning Opera 5.x the proprietory CSS is exactly the same CSS, which Opera use in UI CSS files; Opera 4.x use a little bit different proprietory CSS in UA CSS files as Opera Software once informed in the Web-site).

This CSS is useful for example in a situation, where for Netscape 6.x has been done *.xml documents, which use the XLink linking language, which is supported in Netscape but not in Opera. In order to get the linking to work at least partial in Opera, it is necessary to add to the CSS-file the same CSS, which is primary intended as UI CSS for Opera.

Hopefully Opera supports one day also standard XML linking systems in order to get rid of using propriety CSS in XML-documents. Then the What kind of non-standard (proprietary) CSS browsers support could be used only as UI CSS.

It could be also fair, if Opera Software could announce, that Opera 5.x use proprietary UI CSS (it is not necessary list, which files and how they use it). The company could also tell, that What kind of non-standard (proprietary) CSS browsers support should be be used only in intranet solution, where all people use Opera as the default browser.

Opera Software: Web specifications supported in Opera 5 - the details.


As I have been already mentioned, the proprietary CSS in Opera and new Netscape/Mozilla is not (at least primary) intended for the Internet use. The What kind of non-standard (proprietary) CSS browsers support for MS IE is in principle level different as the proprietary CSS in Opera and Netscape/Mozilla because it is designed especially for Web-authors. The final purpose is is that Web-sites could work properly only in MS IE browsers. This aim violates the basic principles of the WWW and the Internet because WWW is intended as global net community, which use common agreed standards.

The proprietary CSS in MS IE concerns much UI CSS, for example defining the color of scroll bars (for example scrollbar-base-color: #603;). In principle non-standard UI CSS is such CSS, which belongs to UI CSS, when the user could define the presentation of his own browser. Using proprietary UI CSS in common Web-sites is in basic level a little bit questionable. But defining color of scroll bars doesn't cause any harm to other browsers. That's why I have used it in the "link books". Because CSS2 has some UI CSS, the fact that Microsoft calls them as extensions is in this connection appropriate.

Even if proprietary UI CSS belongs in principle among UA CSS, I don't resist the usage of such non-standard UI CSS, which doesn't cause harm to other browsers. Browser designers could even fairly compete, which browser helps visitors to understand better the content of Web-pages without causing any harm to other browser, which also visit in the same pages.

The UI CSS of Opera doesn't have UI CSS features. The proprietary UI CSS of new Netscape/Mozilla includes some UI CSS features. Netscape 6.x doesn't support the outline property, but it has non-standard proprietary properties, which make the same task. In principle they could be used in common Web-sites even if it is not recommendable. Because Netscape/Mozilla doesn't tell about this possibility, it might be impolite to use those properties.