W3C HTML Validated

W3C HTML Validated

The Markup Validator is a free service by W3C that helps check the validity of Web documents. Most Web documents are written using markup languages, such as HTML or XHTML. These languages are defined by technical specifications, which usually include a machine-readable formal grammar (and vocabulary). The act of checking a document against these constraints is called validation, and this is what the Markup Validator does.

How to test ?

First time open w3c website in here

Step 2, you must insert your website/ page url to addres form

and click check button

After checking, you can see error/ problem in your page/website.