Summary  
This chapter covers how to enforce minimum and maximum character length constraints on text input fields using HTML5 minlength and maxlength attributes to leverage built-in browser validation.  

General domain of usage  
Web form input validation

When you want to control how many characters a user can enter in a text field, you can use the HTML5 `minlength` and `maxlength` attributes. These attributes allow you to set the minimum and maximum number of characters that are accepted for an input. This is especially useful for fields like usernames, passwords, or comments, where you want to prevent entries that are too short or too long.

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When you use `minlength` and `maxlength` on an input, browsers automatically check the length of the user's entry when the form is submitted. If the input is shorter than the `minlength` or longer than the `maxlength`, the browser will prevent the form from being submitted and will usually show a built-in error message. This makes it easy to enforce basic length rules without writing any JavaScript.

Which attribute enforces a minimum length on a password field?

Learn how to validate form input, enforce rules, and guide users toward correct and complete submissions using JavaScript. Explore HTML5 validation, custom logic, regular expressions, and asynchronous checks, then apply these concepts to create real-world form behavior. Build clear error messaging, improve usability, and finish with a fully validated signup form that demonstrates form handling best practices.

Learn how to access form elements, read user-entered values, and prepare data for validation. Understand how to handle submit events, clean input, and detect empty fields before running any validation logic.

Use HTML5's built-in validation features to enforce rules with minimal JavaScript. Explore required fields, input types, length limits, pattern matching, and how to check validity programmatically.

Extend validation beyond HTML5 by writing custom rules and reusable functions. Work with regular expressions, validate difficult input patterns, and perform asynchronous checks when needed.

Provide clear feedback with inline messages and visual cues, helping users understand and correct mistakes. Apply all validation techniques to build a fully functional signup form that delivers a smooth, user-friendly experience.

Setting Length Constraints

Awesome!

Setting Length Constraints