Web browsers receive HTML documents from a web server or from local storage and render the documents into multimedia web pages.HTML describes the structure of a web page semantically and originally included cues for the appearance of the document.
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W3C HTML Validation Service
1.Unintuitive error-handling behavior
Certain invalid syntax constructs,when parsed,result in DOM trees that are highly unintuitive.
2.Errors that can result in infoset coercion
< table>< hr>...
For example,it is unclear whether the author intended the following to be an h1 heading or an h2 heading:< h1>Contact details</h2>
Select the file on your computer and click the button to format it.
What is HTML?
HTMLis the core foundational standard being worked on by the WHATWG community.It is continuously maintained and supersedes HTML4,XHTML1,DOM Level 2 HTML,and all previous HTML specifications—addressing many of the shortcomings of those specifications while at the same time enhancing HTML to more adequately cover the needs of web applications.Along with defining the HTML markup language,it also defines many of the core requirements that form the basis of the web runtime.
What is HTML5?
Going forward,the WHATWG is just working on"HTML",without worrying about version numbers.When people talk about"HTML5"in the context of the WHATWG,they usually mean just"the latest work on HTML",not necessarily a specific version.For more details,see the section called"
How do I validate my pages?
Use a HTML.