Opacity

An idea just occurred to me while thinking about a possible website 
design.  Wouldn't it be cool if you could set the opacity of individual 
elements?  I could see some pretty sweet things done with that, many 
ideas from the top of my head.  And, a bit off topic, people could use 
DHTML alongside it for even cooler things.  Just a thought.

The way I see it, the easiest way would be a straight-up opacity 
attribute, which would effect the whole element: text, borders, 
background (including images), etc.  Anything part of the element would 
be included.  You could go more complex and set opacity as an attribute 
for the text, borders, etc. individually, but it might be overkill.  
Just a suggestion.  What do you think?

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