Free SEO Tools

Doctype HTML Declaration Test

Check if your page has a valid HTML doctype declaration. This is important for browser compatibility and rendering consistency.

Frequently asked questions

Have a different question and can't find the answer you're looking for? Reach out to our support team by sending us an email and we'll get back to you as soon as we can.

What is HTML Doctype Declaration?

The DOCTYPE declaration is an instruction to the web browser about what version of HTML the page is written in. It is not an HTML tag, but rather an instruction to the browser about what type of document to expect.

The DOCTYPE declaration must be the very first line of code in an HTML document, before the <html> tag.

Why is HTML Doctype Declaration important?

The DOCTYPE declaration is important for several key reasons:

  1. Browser Rendering Mode: It prevents browsers from switching to "quirks mode" and ensures consistent rendering
  2. Validation: It enables proper HTML validation of your code
  3. Standards Compliance: It ensures your document follows HTML standards
  4. Future Compatibility: It helps maintain compatibility with future browser versions
  5. Error Handling: It improves error handling in browsers
How to add HTML Doctype Declaration to a webpage?

For HTML5 (the current standard), add this as the very first line of your HTML document:

<!DOCTYPE html>

A complete example would look like:

<!DOCTYPE html>
<html>
  <head>
    <title>My Website</title>
  </head>
  <body>
    <!-- Your content here -->
  </body>
</html>

Note: The DOCTYPE declaration is case-insensitive, but uppercase is the conventional way to write it.

Start winning at SEO.
Without paying a fortune.

We offer market-leading SEO tools that are easy to use and affordable, without high monthly fees. Try Today without risks.

Get started Now See Features