Implementing Form Validation in Bootstrap

1. Introduction

1.1 Tutorial Goal

In this tutorial, our main goal is to teach you how to implement form validation in Bootstrap. Form validation is a crucial aspect of web development as it ensures the data collected from users is valid, consistent, and secure.

1.2 Learning Outcomes

By the end of this tutorial, you will be able to:
- Understand the concept of form validation
- Implement form validation using Bootstrap
- Display appropriate error messages based on user input

1.3 Prerequisites

A basic understanding of HTML, CSS and JavaScript is required. Familiarity with Bootstrap is also beneficial, but not necessary.

2. Step-by-Step Guide

Bootstrap provides built-in form validation classes that make implementing validation easy. It checks the form inputs against the specified rules and displays corresponding error messages.

2.1 Form Validation Classes

The form validation classes in Bootstrap are:

• .was-validated class: This class is added to the <form> element to validate all the form inputs.
• .is-valid class: This class is added to an input element to indicate valid input.
• .is-invalid class: This class is added to an input element to indicate invalid input.

2.2 Displaying Error Messages

Error messages can be displayed using the .invalid-feedback class. The text within this class is displayed when the input is invalid.

3. Code Examples

Here are some examples of how to implement form validation in Bootstrap.

3.1 Example 1: Simple Form Validation

<form class="was-validated">
  <div class="form-group">
    <label for="name">Name:</label>
    <input type="text" class="form-control" id="name" required>
    <div class="invalid-feedback">Please enter your name.</div>
  </div>
</form>

In this example, the required attribute is used to make the name field mandatory. If the user tries to submit the form without entering a name, the text within the .invalid-feedback class is displayed.

4. Summary

In this tutorial, you've learned how to implement form validation in Bootstrap. You've learned how to check user input against certain criteria and how to display appropriate error messages.

To learn more about form validation and other Bootstrap components, refer to the official Bootstrap documentation.

5. Practice Exercises

5.1 Exercise 1

Create a form with fields for name, email, and password. Implement validation to ensure all fields are filled out and display an error message if they are not.

5.2 Exercise 2

Expand the form from Exercise 1 to include a field for age. Implement validation to ensure the age entered is a number and is not less than 18.

5.3 Solutions

For solutions and further explanations, refer to the official Bootstrap documentation. Remember, the best way to learn is by practicing, so try to solve the exercises on your own before looking at the solutions.

Happy coding!