What is a validation tool, and why is it
important.
There are many browsers, such as Internet
Explorer, Netscape Navigator, Mozilla, Opera, et al., and each
of them has different versions, such as IE 6, 5.5, 5, 4, Netscape
7, 6.2, 4.x ad nauseum. Add to this mix the various platforms
(with their different versions): Windows, Macintosh, Linux.
The problem with all these differences is that they do not always
handle every webpage in the same manner, not only is HTML displayed
a bit different, but more advanced options such as CSS also
cause problems. Sometimes these differences are minor, but other
times the differences will render a page unreadable to people
using certain browsers on certain platforms. Validation tools
work to tell you what is and what is not compatible on your
website.
Webmonkey has a good basic
article on validation tools
Validation tools:
W3C' s validator
tool
WDG HTML
Validator
HTML
Authoring Services
(has various options for checking different options.)
Many others are available at
the Google
Web Directory