MarkUp Validation Service

The W3 MarkUp Validation Service validates a  HTML 4.01  
even with obvious errors on page:
e.g.
<script type="javascript"> is reported as valid (it won't work in 
a browser), should be <script type="text/javascript">

if in DOCTYPE there is a mistake, eg. Transititional instead of 
Transitional it is reported as valid.