Chapter 13
Beginner
8 min read
Forms & Input
Form Validation
HTML5 built-in validation lets you check user input before it is sent to a server — without writing any JavaScript.
🎯 What you'll learn
✓Use required to make fields
mandatory
✓Use pattern for regex validation
✓Use min and max for number
ranges
✓Show custom validation messages
Introduction to Form Validation
This chapter covers Form Validation in depth. Understanding this topic is essential for writing clean, modern HTML. Use the live editor below to experiment as you read.
💡 In This Chapter
You will see real code examples, clear
explanations, and
a live editor to practice immediately — no setup needed.
Required
Make field mandatory.
HTML
<input type="email" required>
<input type="text" required minlength="3">Pattern
Regex validation.
HTML
<input type="text" pattern="[A-Za-z]{3,}" title="3+ letters only">
<input type="number" min="1" max="100">Try It Yourself
Edit the code below and click ▶ Run to see your changes live.
Live Editor
✎ Editor
👁 Preview
❓ Quick Check — Chapter 13
Which attribute makes an input field mandatory to fill?
📄 Chapter Summary
- Use required to make fields mandatory
- Use pattern for regex validation
- Use min and max for number ranges
- Show custom validation messages