Ian Hickson (2009-02-13):
There are three of these attributes so far:
autocomplete = on/off
contenteditable = true/false
draggable = true/false
It would be nice, actually, from an author perspective at least, if
all of these worked for all applicable attributes:
<foo bar>
<foo bar=bar>
<foo bar=on>
<foo bar=true>
<foo bar=1>*
<foo>*
<foo bar="">*
<foo bar=off>
<foo bar=false>
<foo bar=0>*
* I am not completely sure about the ones marked with an asterisk,
because digits may not be necessary and the default or inherited
state may be 'enabled'.
