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HTML <!DOCTYPE> Tag: Definition, Syntax, and Examples

What is HTML <!DOCTYPE> Tag?

The HTML <!DOCTYPE> tag is used to tell the browser which version of HTML the webpage is written in. It helps the browser render the page correctly by switching it into standards mode instead of quirks mode. The <!DOCTYPE> tag is not an HTML element and does not have a closing tag. This declaration is always placed at the very top of the HTML document before the html tag. Every webpage must include one <!DOCTYPE> declaration to ensure correct rendering and compatibility across browsers.

Syntax of the HTML <!DOCTYPE> Tag

plaintext
<!DOCTYPE html>

This is the standard syntax for HTML5. It begins with <!DOCTYPE and ends with html. It tells the browser to use the HTML5 standard.

Examples of HTML <!DOCTYPE> Tag

Example 1: Basic HTML5 DOCTYPE

plaintext
<!DOCTYPE html>
<html lang="en">
<head>
<title>Welcome to Scholar247</title>
</head>

<body>
<h1>Hello, World!</h1>
</body>

</html>

In this example, the page uses the simple HTML5 DOCTYPE declaration at the top to ensure modern browser compatibility.

Example 2: SEO-Optimized Webpage Using DOCTYPE

plaintext
<!DOCTYPE html>
<html lang="en">

<head>
<title>Best Learning Resources Online | Scholar247</title>
</head>

<body>
<h1>Welcome to Scholar247 Learning Hub</h1>
<p>Find the best online study materials and tutorials.</p>
</body>

</html>

This example includes an SEO-friendly title and a proper HTML5 DOCTYPE, which helps ensure clean rendering and better performance across all devices and browsers.

Attributes of the <!DOCTYPE> Tag

The <!DOCTYPE> tag does not support any attributes.
It is a simple declaration that only defines the HTML version used by the page.

Best Practices for <!DOCTYPE> Tag

• Always place the <!DOCTYPE> tag at the very top of the HTML file.
• Use the HTML5 DOCTYPE (<!DOCTYPE html>) for modern websites.
• Avoid older DOCTYPE versions unless working on legacy projects.
• Ensure there is no space or text before the DOCTYPE declaration.
• Use a single DOCTYPE per page to avoid rendering issues.

FAQs About the HTML <!DOCTYPE> Tag

What is the purpose of the <!DOCTYPE> tag?

The <!DOCTYPE> tag tells the browser which HTML standard the webpage uses, ensuring proper rendering and layout.

Does the <!DOCTYPE> tag affect SEO?

Indirectly yes. A proper DOCTYPE helps browsers render pages correctly, improving page performance and user experience, which are important for SEO.

Can I use multiple <!DOCTYPE> tags on a page?

No. Only one <!DOCTYPE> declaration should be used, and it must be placed at the top of the document.

Is the <!DOCTYPE> tag case-sensitive?

No. <!DOCTYPE html> works the same as <!doctype html>, but uppercase is recommended as the standard.

What happens if the <!DOCTYPE> tag is missing?

Browsers may switch to quirks mode, which can break layouts, cause inconsistent rendering, and affect page compatibility.

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