1.Markup Validation Service
用途：This validator checks the
markup validity of Web documents in HTML, XHTML, SMIL, MathML, etc. If you wish to validate specific content such as
RSS/Atom feeds orCSS stylesheets,
MobileOK content, or to
find broken links, there are
other validators and tools available.
2.CSS Validation Service
http://jigsaw.w3.org/css-validator/
用途：CSS的合法性检查
3. HTML,JavaScipt,CSS方法，属性的参照网站
http://help.dottoro.com/ljarvfic.php
在平常的web开发中查查资料来说还是有用的。