10.9.2011 6:38, Mary Villanueva wrote:
What does it mean or do when one sets an ID selector to an
HTML element such as the one below?
Setting an attribute like id="blueDropdowns" to an HTML element does not
as such have any effect on rendering. In functionality, it means that
the element can be a target of a link (that uses a URL ending with
#blueDropdowns) and can be conveniently accessed in client-side
JavaScript; these things do not affect styling but they are often part
of the reason of using the attribute.
It seems to be acting as a class in this case
No, it’s not acting as a class, but an ID selector such as
#blueDropdowns can be used in many situations where a class selector
would be another option. The difference is that ID selector matches (at
most) one element in a document whereas a class selector may match many
elements (and often does). The reason is that an id attribute value must
be unique within a document.
I want to understand this syntax so that I can
be assured that I'm not inadvertently building something that is going to
fall apart in IE8 backwards.
Id selectors as well as simple class selectors are as safe as you can
get – the selector types that have been supported by CSS-enabled
browsers from the beginning.
This, however, applies only when id and class attributes are used
correctly. If two or more elements in a document have the same id
attribute value, all bets are off. Anything may happen.
I also have the other dropdown menus set to classes as shown in the example
below. I’m doing this because I need to be able to space the elements
precisely.
<ul id="blueDropdowns" class=”About”>
So do you have id="blueDropdowns" on more than one element? Somehow I
read between lines that this might be the case. Then you should use
class attributes and class selectors. Note that you can assign two
classes to an element, e.g.
class="blueDropdowns About"
(which works well, ever since Netscape 4 stopped being an issue).
(And do you use curly quotation marks in attribute specifications? The
attribute class=”About” is correct as per HTML5 but means that the
quotation marks are part of the attribute value!)
And here’s the partial CSS for the dropdown menus. I hope it’s enough to
help.
People say that a URL says more than a thousand words, but that’s really
an understatement. Here the main problem, if there is a problem, appears
to be in HTML markup, not in CSS code.
--
Yucca, http://www.cs.tut.fi/~jkorpela/
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