kayodeok said:
Strange! But after enclosing with the Form element,
http://www.htmlhelp.com/tools/validator/direct.html
says it is valid.
It's not that strange, and it's equally valid without any form element.
Just bear in mind that "valid" only means compliance to some formal
rules, see
http://www.cs.tut.fi/~jkorpela/html/validation.html
I don't know what you are trying to achieve so this is my
best guess:
<form action="..." method="post">
There's no need to guess, and no need to use a form.
The markup, as given in the original question, has a simple list of
links. That's the best navigational tool ever invented; forms are poor
and confusing surrogates.
But the fieldset markup around it, although valid (remember that this
only means compliance to some formal rules, which _must_ allow a lot of
nonsense in any real application), is rather illogical. There are no
form fields around, and no fields are called for.
If, on the other hand, you really really want the visual appearance of
a fieldset and its legend, as implemented in some particular
browser(s), then such markup is what you need. The appearance cannot be
described in current CSS. Well, you can come pretty close I suppose, by
drawing a border around the <ul> element and by using a negative margin
to position the header-like text to that it appears on top of a segment
of the border. But then it would probably be _too_ close a fieldset
appearance to confuse the user but not close enough to please the
designer!