CSS HTML Validator is a powerful tool but it does have its limits. Please keep in mind the below as you use CSS HTML Validator to create quality documents.
•CSS HTML Validator does not and cannot completely check a document for 100% correct syntax. However, it will detect many syntactical errors including most common errors such as misspelled tag names, attributes, and attribute values, missing quotation marks, missing end tags, mismatching '<' and '>' characters, and using tags in incorrect locations. Using CSS HTML Validator is far better than not using anything at all. "It is better to have validated and failed than never to have validated at all."
•(This should not be considered a limitation) HTML 4.0 does not require "head" and "body" tags but due to the current design of enforcing good style, these tags are required for proper validation (and it's always safer to have them than to not). In addition, some tags may need to have end tags for proper validation by HTML Validator (such as "td") even though in HTML 4.0 they do not have to be. Many web developers and companies, including AI Internet Solutions LLC, the developers of CSS HTML Validator, would not consider this a limitation, but would instead consider it to be good style and structure. Furthermore, XHTML makes using many end tags a requirement (like with the "td" element).
NOTE: It is important to note that CSS HTML Validator's own validation engine is not a "real" HTML Validator in the strict technical definition of "HTML validator". This means that CSS HTML Validator is not limited to checking HTML documents according to a DTD (document type definition). Instead, it uses a powerful validation engine that is custom designed for HTML, XHTML, and CSS. It does not use DTDs. However, a separate SGML based DTD parser and validator (nsgmls) is included with CSS HTML Validator Std+ and can be used for DTD based HTML validation.
Because CSS HTML Validator's own validation engine is not a DTD validator, it can:
•Check HTML5 (including HTML 5.1, 5.2, etc.)
•Detect many problems that a DTD validator cannot detect.
•Enforce better style.
•Provide tips, compatibility messages, and advice (most of these types of messages require the standard or higher edition).
•Display easier to understand validator messages.
•Be customized and configured to a user's specifications.
•Check HTML (or XHTML), CSS, links, SEO, accessibility, and spelling all at once.