- From: nir dagan <dagan@upf.es>
- Date: Sat, 28 Mar 98 20:58:12 MET
- To: w3c-wai-gl@w3.org
- Cc: dagan@upf.es
Let me try to put some order regarding the usage of horizontal rules, both "normal" and graphical. 1. General purpose of horizontal rules: horizontal rules are used as dividers withing a document. The concept originates from print medium. In visual media the exact meaning of the rule is understood by the surrounding blocks of text, as well as the width of the rule and possibly other visual features such as color or style (dotted, inset etc.) 2. Horizontal rules in HTML documents: 2.1 The HR element. In the strict version of HTML 4.0 its appearance in visual and other media can be affected by stylesheets. HR accepts the title attribute, that allows authors to associate text to the rule. HTML 4 transitional allows to effect the visual presentation of a rule by choosing its width (relative to window's width), size (thickness), alignment (relative to window). Some user agents suport a color attribute (that does not exist in any spec that I know of) 2.2 Graphical and "styled" rules. Stylesheets can be used to add style to the rule (using border properties) its width (using margins and text alignment) etc. Also by defining padding and a background image to a HR element one can create a graphical rule. (in this regard there is an interesting article by Flavell, excuse me for not mentioning the exact reference) An advantage of this method is that the width of the rule is detrmined by the window's width, and is not fixed in pixels like when using IMG. Another way is not to use the HR element, but to insert a graphical rule using the IMG element. Some authors use a TABLE and color the (textless) cells in order to create a multicolor rule. 3. Problems with non-visual media: Users of non-visual media cannot understand the the meaning of the rule via its visual aspects. Thus we ask: What method (HR or IMG) is preferable? How to associate text with a rule (title, alt etc) What text makes sense. 4. My opinion for accessibility guidelines: 4.1. Using the HR element is preferrable to using IMG or other elements. Stylesheets may be used to create a large variety of colors, styles, and background images, for the visual media. 4.2. The title attribute is the only way to associate text to the HR element. The text should generate the function of the rule. E.g., <HR title="Footnotes:"> or <HR title="End of example"> "Deprecated" methods: 4.3. In case one uses the IMG element the alt attribute should be used for generating the function of the rule. e.g.: <DIV align=center><IMG src="rule.gif" alt="Footnotes:"></DIV> 4.4. In case one uses a TABLE and coloring the cells. In this case, it seems the best is to use the title of the table for providing text and put nbsp characters in all cells. Note: I am very much against drawing the rule (in the alt) even in addition to text. This method is very much platform dependent and relies on the appearance of rules in visual non graphical user agents (notably Lynx), but doesn't make much sense otherwise. 5. Misuse of the HR element. Some authors use the HR element to create decoration to headings etc. This usage of HR should be deprected in favor of stylesheets. Regards, Nir Dagan.
Received on Saturday, 28 March 1998 15:05:13 UTC