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HTML for Kids · Lesson

Validating Your HTML

Ensure your code follows HTML standards.

Validating Your HTML is a free HTML for Kids lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the HTML for Kids learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

1

Validating Your HTML

Welcome to the next lesson! Today, we’ll learn how to validate your HTML code to ensure it follows web standards and is error-free. Validation helps you create better web pages.

Validating Your HTML — illustration 1

2

What is HTML Validation?

Validation checks your HTML code to make sure it is written correctly according to web standards.

Benefits of validating your HTML:

  • Ensures your code is error-free.
  • Makes your page compatible with all browsers.
  • Improves accessibility and SEO.

3

Common HTML Errors

Here are some common mistakes to avoid:

  • Missing closing tags.
  • Using incorrect tag names.
  • Forgetting to use quotation marks around attribute values.

Example: A common mistake:

<a href=https://example.com>Click here<a>

Corrected version:

<a href="https://example.com">Click here</a>

4

Using the W3C Validator

The W3C Validator is a free tool that checks your HTML code for errors and warnings. Follow these steps:

  1. Go to validator.w3.org.
  2. Choose one of the following options:
    • Direct Input: Paste your HTML code.
    • File Upload: Upload your HTML file.
    • URL: Enter the URL of your web page.
  3. Click Check to see the results.

5

Fixing Validation Errors

When you validate your code, the validator will list any errors or warnings. Here’s how to fix them:

  • Read the error message carefully.
  • Locate the problem in your code.
  • Make the necessary corrections.

Tip: Always re-validate your code after making changes!

6

Best Practices for Validation

Follow these tips to avoid validation errors:

  • Always use the correct document type declaration (e.g., <!DOCTYPE html>).
  • Close all tags properly.
  • Use lowercase letters for tag names.
  • Include the alt attribute for images.

Example:

<!DOCTYPE html>
<html>
  <head>
    <title>Validated Page</title>
  </head>
  <body>
    <h1>Welcome to My Page</h1>
    <img src="image.jpg" alt="Description of the image" />
    <p>This is a valid HTML page.</p>
  </body>
</html>

7

Real-World Example

Here’s an example of a page with validation issues:

<!-- Incorrect HTML -->
<!DOCTYPE html>
<html>
  <head>
    <title>My Page</title>
  <body>
    <h1>Welcome</h1>
    <img src="image.jpg">
    <p>This is my first page.
  </body>
</html>


<!-- Correct HTML -->
<!DOCTYPE html>
<html>
  <head>
    <title>My Page</title>
  </head>
  <body>
    <h1>Welcome</h1>
    <img src="image.jpg" alt="A sample image">
    <p>This is my first page.</p>
  </body>
</html>

8

Try It Yourself

Let’s create a valid HTML page. Use this example:

<!DOCTYPE html>
<html>
  <head>
    <title>Validation Example</title>
  </head>
  <body>
    <h1>My Validated Page</h1>
    <img src="example.jpg" alt="An example image">
    <p>This page passes validation!</p>
  </body>
</html>

9

10

Great Job!

Congratulations! You’ve learned how to validate your HTML code and fix common errors. Validation is a crucial step in creating professional, accessible, and browser-compatible web pages. In the next lesson, we’ll move on to advanced topics and fun challenges to solidify your skills. Keep up the great work!

Validating Your HTML — illustration 10

Frequently asked questions

Is the “Validating Your HTML” lesson free?

Yes — the full text of “Validating Your HTML” is free to read here on the web, and the HTML for Kids course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the HTML for Kids course, upgrade to CoddyKit PRO.

What will I learn in “Validating Your HTML”?

Ensure your code follows HTML standards. You practise HTML for Kids with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start HTML for Kids?

No prior experience is required. HTML for Kids on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Validating Your HTML” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this HTML for Kids lesson?

Yes. Every HTML for Kids lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. Writing Clean Code
  2. Accessibility Basics
  3. Validating Your HTML
  4. HTML Comments
← Back to HTML for Kids