W3C

What do you have to do with Web Tidy, the web page code fixer, to get
a site running properly?

I opened this page just now and found it an inexact science in
Firefox:
http://www.nmm.ac.uk/server/show/conWebDoc.5458



This page is not Valid XHTML 1.0 Strict!
Result: Failed validation, 2 Errors
Address: http://www.nmm.ac.uk/server/show/conWebDoc.5458
Encoding: utf-8
Doctype: XHTML 1.0 Strict
Root Element: html
Root Namespace: http://www.w3.org/1999/xhtml

Validation Output: 2 Errors

1. Error Line 7, Column 175: there is no attribute "border".

…img/clock_20030415133752.gif" border="0" //a/span

✉

You have used the attribute named above in your document, but
the document type you are using does not support that attribute for
this element. This error is often caused by incorrect use of the
"Strict" document type with a document that uses frames (e.g. you must
use the "Transitional" document type to get the "target" attribute),
or by using vendor proprietary extensions such as "marginheight" (this
is usually fixed by using CSS to achieve the desired effect instead).

This error may also result if the element itself is not
supported in the document type you are using, as an undefined element
will have no supported attributes; in this case, see the element-
undefined error message for further information.

How to fix: check the spelling and case of the element and
attribute, (Remember XHTML is all lower-case) and/or check that they
are both allowed in the chosen document type, and/or use CSS instead
of this attribute. If you received this error when using the embed
element to incorporate flash media in a Web page, see the FAQ item on
valid flash.
2. Error Line 23, Column 9: there is no attribute "align".

p align="right"span class="imageCaption"Looking down to the
north pole, the

✉

You have used the attribute named above in your document, but
the document type you are using does not support that attribute for
this element. This error is often caused by incorrect use of the
"Strict" document type with a document that uses frames (e.g. you must
use the "Transitional" document type to get the "target" attribute),
or by using vendor proprietary extensions such as "marginheight" (this
is usually fixed by using CSS to achieve the desired effect instead).

This error may also result if the element itself is not
supported in the document type you are using, as an undefined element
will have no supported attributes; in this case, see the element-
undefined error message for further information.

How to fix: check the spelling and case of the element and
attribute, (Remember XHTML is all lower-case) and/or check that they
are both allowed in the chosen document type, and/or use CSS instead
of this attribute. If you received this error when using the embed
element to incorporate flash media in a Web page, see the FAQ item on
valid flash.