Form Validation in JavaScript

Form validation is the process of checking if user input is correct before submitting a form. For example: Making sure an email is valid Ensuring a password is long enough Preventing empty fields Confirming passwords match Validation improves user experience and prevents bad data from being sent to the server. Why Form Validation Is Important Prevents empty submissions Reduces server errors Improves security Gives instant feedback to users There are two types of validation: Client-side validation (in the browser using JavaScript) Server-side validation (on the backend) In this article, we focus on JavaScript (client-side validation). Basic Example: Prevent Empty Fields HTML <form id="myForm"> <input type="text" id="username" placeholder="Enter username"> <button type="submit">Submit</button> </form> JavaScript document.getElementById("myForm").addEventListener("submit", function(event) { let username = document.getElementById("username").value; if (username === "") { event.preventDefau