Doctype Test

Verifies that the page has a modern HTML doctype declaration.

What is this check?

The Document Type Declaration (Doctype) is the very first line of an HTML document. It tells the browser which version of HTML the page is written in.

Why is it important?

A proper doctype ensures the browser renders the page in 'standards mode,' following modern web specifications. Without it, browsers may enter 'quirks mode,' which can lead to inconsistent and unpredictable visual rendering.

What is the impact?

A missing or incorrect doctype can cause significant CSS and layout issues across different browsers.

Example Implementation

<!DOCTYPE html>
<html>
<head>
  ...
</head>
<body>
  ...
</body>
</html>