A lengthier answer to this question is also available on this site if the explanation above did not satisfy you.
The Markup Validator is maintained at by W3C staff and benevolent collaborators, who receive a lot of help from contributors (read the full credits).
With these concepts in mind, we can define "markup validation" as the process of checking a Web document against the grammar (generally a DTD) it claims to be using.
Validity is one of the quality criteria for a Web page, but there are many others.
You can validate templates locally by using the aws cloudformation validate-template --template-body file:///home/local/test/A client error (Validation Error) occurred: Template format error: JSON not well-formed.
The validation result was certainly positive ("this page is valid..."), but if it wasn't, you would probably do the author of the page where the icon was a favor if you could warn him/her of this abnormal situation.
To check the operational validity, you need to attempt to create the stack.There are other possible uses and a few usage options, please read the user's manual for further help with this service.If, for some reason, you prefer running your own instance of the Markup Validator, check out our developer's documentation.In other words, a Web page has little chance of being a good web page.For that reason, the fact that the W3C Markup Validator says that one page passes validation does not mean that W3C assesses that it is a good page.That's why you want to follow the first half of the maxim by making sure your pages are legal HTML.The best way to do that is by running your documents through one or more HTML validators.However, Just as texts in a natural language can include spelling or grammar errors, documents using Markup languages may (for various reasons) not be following these rules.The process of verifying whether a document actually follows the rules for the language(s) it uses is called .command is designed to check only the syntax of your template.It does not ensure that the property values that you have specified for a resource are valid for that resource.