[whatwg] De-emphasis

Arve Bersvendsen arveb at opera.com
Fri Feb 9 03:24:54 PST 2007

On Fri, 09 Feb 2007 11:58:35 +0100, Mikko Rantalainen  
<mikko.rantalainen at peda.net> wrote:

> I believe that <aside> and <small> are different from de-emphasis (that  
> would be <dem> IMHO). However, the <dem> element wouldn't be that often  
> used and it would be vital for it to be easily implemented. A new  
> element with specified semantics and a simple default CSS style would be  
> a nice choice. An example *implementation* could be a single CSS rule:
> 	dem { opacity: 0.8 }
> How hard it would be to implement the behavior David described above?  
> Take any existing UA as a base.

If you are talking about making a backwards-compatible approach: Very  
cumbersome, as MSIE constructs a rather peculiar HTML DOM for elements it  
doesn't recognize. Compare this example:  
in MSIE and other browsers:

IE makes two empty elements, whose tag names are 'dem' and '/dem'  
respectively. While this may often be of little consequence for a rendered  
view and you don't attempt to change the value of CSS display:, it may  
wreak havoc in scripting scenarios.

Confusingly enough, if try to create the document tree with scripting,  
using something like ...

var p = document.createElement('p')
p.appendChild(document.createTextNode('Some '));
var dem = document.createElement('dem');
document.appendChild(document.createTextNode(' text');

... MSIE will create the correct document tree. Amusing, isn't it?

Note that this is a general problem with all new non-empty elements  
introduced in HTML5, they will break any scenario in which the DOM is to  
be scripted, or require separate code paths for autocorrecting the DOM in  
those browsers.

Arve Bersvendsen, Web Applications Developer

Opera Software ASA, http://www.opera.com/

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