( Please note: you can test all externally visible CS web pages by appending the ,toolname to the URL. See the ,tools service for more information.)
You should use the various services listed below to check whether your web page validates. An example web page is provided to enable you to easily see how these checkers work. Please note that external services can only be used to check web pages in the external view. Local web pages (.local) are inaccessible to these services.
At the time of writing there were no validation checkers which can comprehensively check web pages against the WAI Guidelines. Instead, you should use them as a guide in conjunction with a manual review of a web page.