a element is the element with the attribute
used by the most pages:
In addition to the almost ubiquitous use of
around half of pages in the sample had at least one
element with a
target attribute (determining whether
these are mostly attempts to make links open in new windows or tabs
or whether they are indicative of frames use would require further
research; the first seems most likely, however, since frames in
general aren't used much).
A lot of pages use the
title attribute on
a elements, which is good. On the other hand, the high
frequency of occurrences of
a elements is a little worrying; presumably those are
mostly cases of the status bar being overridden. If so, the fact
that there are noticeably fewer
in use on
a elements is probably a sign of rampant bad
UI. Thankfully for users, most Web browsers these days prevent the
status bar from being changed by scripts.
rel attribute is not used all that
much, but it is still used enough to matter. Here are the most
nofollow value was originally announced by Google
in conjunction with some other vendors, but has apparently now
gotten much wider industry support.
is part of the rel-license microformat, and is propagated by the
Creative Commons movement.
external seems to be mainly
propagated by WordPress, but people have long been asking for a way
to label their links as being external vs
bookmark is the de-facto "permalink" link
type (which we all pretend is what HTML4 meant by its ridiculously
tag is a big part of the recent
"Web 2.0 collaborative remixability social tagging"
help are HTML4 values, with relatively well-defined
meanings (though it is possible that the reason
start have roughly the same
popularity is that a lot of people are writing
alternate is mostly
used for feeds.
sidebar is an Opera and Firefox value
that makes the link appear in the browser's sidebar.
;="" attributes, which
are apparently relatively common, are indicative of bad
markup. There's a lot of that about. Another "attribute" that is
seen a lot on
a elements (though not in the top
http:. These comes from things like
<a href http://www.example.com/; title "">...</a>
This example would result in an
a element with six
"". For similar reasons, the "attributes"
false are used measurably often on this
Other strange attributes that are used on
alt (a lot!),
(none of which have any effect on browsers, but all of which were
probably intended for other elements in the vincinity of the
a). Interestingly, all of these are used on more pages
rev attribute, which is used so rarely that
it didn't even appear in the top fifty attributes on the
a element in our study.
coords attribute is, much like the
rev attribute, basically never used. This indicates
that the ability to use image maps with
area elements is simply not used. In
attributes are used a little.
From the point of view of changes to the specifications, these
findings are quite important. The rarity of
coords suggests that those features could be removed
from HTML without any difficulty. In contrast, the
ping attribute, proposed
in HTML5, didn't appear on the list at all, so it is likely
that adding it will not cause any problems on existing sites.