HTML and CSS Reference
In-Depth Information
<option value="brie">Brie</option>
</optgroup>
</select>
The preceding markup would render as shown in
Figure 4-22
.
Figure 4-22.
A
select
menu organized with multiple
optgroup
elements
The
optgroup
element is a clear example of using the right tag for the right job. A
benefit of using
optgroup
elements to divide your
option
elements is that the
op-
tgroup
label cannot be selected, nor can its value be submitted as data, whereas in the
former example the page author would either have to live with erroneous submissions or
provide a client- or server-side validator to ensure such dividers had not been submitted.
Additionally, the
optgroup
element has a Boolean
disabled
attribute, which can
be used to disable whole groups of
option
elements, if required.
Text boxes
The
textarea
element is similar in some ways to the text
input
element, but it al-
lows multiple lines of input rather than just one. It uses a pair of attributes,
cols
and
r
ows
, to control its size, and instead of using a
value
attribute to preset any textual
content, it uses the content of the element itself. It's a container element, rather than a
self-closing empty element.
The following code creates a
textarea
that is 20 columns wide and 5 rows high (a
scrollbar will appear if the input exceeds the visible area).
<textarea
cols="20"
rows="5">Type
your
content
here</textarea>
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