How to Build a Modern, Responsive Login & Registration Form with HTML, CSS, and JavaScript (Step-by-Step Guide)

In today’s web development landscape, providing a smooth and intuitive user experience is essential, especially when it comes to something as important as user authentication. In this post, we’ll walk through the process of building a clean, responsive login and registration form. We’ll cover everything from the basic HTML structure to the subtle design touches that make your forms feel modern and user-friendly. Let’s dive in!

Getting Started: The HTML Structure

We begin with a basic HTML5 structure that sets the stage for our login and register forms. Here’s a brief look at the code snippet that forms our foundation:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- BOXICONS -->
    <link href='https://unpkg.com/boxicons@2.1.4/css/boxicons.min.css' rel='stylesheet'>
    <!-- CSS -->
    <link rel="stylesheet" href="css/style.css">
    <title>Login & Register | Ludiflex</title>
</head>
<body>
    <div class="wrapper">
        <div class="form-header">
            <div class="titles">
                <div class="title-login">Login</div>
                <div class="title-register">Register</div>
            </div>
        </div>
        <!-- LOGIN FORM -->
        <form action="#" class="login-form" autocomplete="off">
            <!-- Login form inputs -->
        </form>
        <!-- REGISTER FORM -->
        <form action="#" class="register-form" autocomplete="off">
            <!-- Register form inputs -->
        </form>
    </div>

    <script src="js/script.js"></script>
</body>
</html>

Key Points in Our HTML:

Semantic Markup: The use of semantic HTML elements such as <form> and <input> helps improve accessibility and maintainability.
Responsive Design: The meta viewport tag ensures our forms render well on different devices.
External Libraries: We link to Boxicons for attractive iconography, which enhances the overall user experience.
Styles and Scripts: External CSS (css/style.css) and JavaScript (js/script.js) files allow us to keep our HTML clean and our code modular.

Crafting the Login Form

Let’s take a closer look at the login form. Notice how each input field is wrapped in an input-box div that includes not only the <input> element but also a <label> and an icon:

<!-- LOGIN FORM -->
<form action="#" class="login-form" autocomplete="off">
    <div class="input-box">
        <input type="text" class="input-field" id="log-email" required>
        <label for="log-email" class="label">Email</label>
        <i class='bx bx-envelope icon'></i>
    </div>
    <div class="input-box">
        <input type="password" class="input-field" id="log-pass" required>
        <label for="log-pass" class="label">Password</label>
        <i class='bx bx-lock-alt icon'></i>
    </div>
    <div class="form-cols">
        <div class="col-1"></div>
        <div class="col-2">
            <a href="#">Forgot password?</a>
        </div>
    </div>
    <div class="input-box">
        <button class="btn-submit" id="SignInBtn">Sign In <i class='bx bx-log-in'></i></button>
    </div>
    <div class="switch-form">
        <span>Don't have an account? <a href="#" onclick="registerFunction()">Register</a></span>
    </div>
</form>

Highlights:

Floating Labels: The labels for each input are placed after the input element, which can be styled to create a floating label effect. This not only looks modern but also improves usability.
Icon Usage: Using icons (via Boxicons) next to each input field adds a visual cue that helps users quickly understand what each field represents.
User Flow: A “Forgot password?” link is included, and there’s an easy transition to the registration form with a call-to-action at the bottom.

Building the Register Form

The registration form follows a similar structure but includes a few additional elements to accommodate the registration process:

<!-- REGISTER FORM -->
<form action="#" class="register-form" autocomplete="off">
    <div class="input-box">
        <input type="text" class="input-field" id="reg-name" required>
        <label for="reg-name" class="label">Username</label>
        <i class='bx bx-user icon'></i>
    </div>
    <div class="input-box">
        <input type="text" class="input-field" id="reg-email" required>
        <label for="reg-email" class="label">Email</label>
        <i class='bx bx-envelope icon'></i>
    </div>
    <div class="input-box">
        <input type="password" class="input-field" id="reg-pass" required>
        <label for="reg-pass" class="label">Password</label>
        <i class='bx bx-lock-alt icon'></i>
    </div>
    <div class="form-cols">
        <div class="col-1">
            <input type="checkbox" id="agree">
            <label for="agree"> I agree to terms & conditions</label>
        </div>
        <div class="col-2"></div>
    </div>
    <div class="input-box">
        <button class="btn-submit" id="SignUpBtn">Sign Up <i class='bx bx-user-plus' ></i></button>
    </div>
    <div class="switch-form">
        <span>Already have an account? <a href="#" onclick="loginFunction()">Login</a></span>
    </div>
</form>

Highlights:

Additional Fields: The registration form includes an extra field for the username, which is often required during sign-up.
Terms and Conditions: There’s a checkbox for users to agree to the terms and conditions. This small detail is crucial for compliance and user trust.
Smooth Navigation: Just like the login form, there’s a clear call-to-action that encourages users who already have an account to log in, creating a seamless transition between the two forms.

Enhancing the Experience with CSS and JavaScript

CSS Styling

While our HTML provides the structure, CSS brings our forms to life. In your css/style.css file, you can define styles for the wrapper, forms, input fields, and buttons. Some useful CSS techniques include:

Flexbox or Grid: Use these layout models to center your forms and ensure they’re responsive.
Transitions and Animations: Smooth transitions on focus or hover states for inputs and buttons improve the user experience.
Responsive Design: Media queries help adapt the form layout to various screen sizes, ensuring usability on mobile devices.

/* IMPORT FONT */
@import url('https://fonts.googleapis.com/css2?family=Poppins:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&display=swap');

/* COLOR VARIABLES */
:root {
    --primary-color: #0D1936;
    --secondary-color: #535354;
    --background-color: #EFEFEF;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --white-color: #FFF;
    --black-color: #000;
    --input-border-color: #E3E4E6;
    --transition-3s: 0.3s;
}

/* GLOBAL STYLES */
*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

/* REUSABLE ELEMENTS */
a{
    text-decoration: none;
    color: var(--black-color);
    transition: var(--transition-3s);
}
a:hover{
    text-decoration: underline;
}

body{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: var(--background-color);
}

/* WRAPPER */
.wrapper{
    position: relative;
    width: 430px;
    height: 500px;
    background-color: var(--white-color);
    border-radius: 15px;
    padding: 120px 32px 64px;
    border: 1px solid var(--primary-color);
    box-shadow: 0 8px 15px var(--shadow-color);
    transition: var(--transition-3s);
    overflow: hidden;
}
/* FORM HEADER */
.form-header{
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 140px;
    height: 70px;
    background-color: var(--primary-color);
    border-radius: 0 0 20px 20px;
}
.form-header::before, .form-header::after{
    content: "";
    position: absolute;
    top: 0;
    width: 30px;
    height: 30px;
}
.form-header::before{
    left: -30px;
    border-top-right-radius: 50%;
    box-shadow: 15px 0 0 var(--primary-color);
}
.form-header::after{
    right: -30px;
    border-top-left-radius: 50%;
    box-shadow: -15px 0 0 var(--primary-color);
}
/* TITLES */
.titles{
    position: relative;
}
.title-login, .title-register{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    color: var(--white-color);
    font-size: 24px;
    transition: var(--transition-3s);
}
.title-register{
    top: 50px;
}

/* FORMS */
.login-form, .register-form{
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 85%;
    transition: var(--transition-3s);
}
.register-form{
    left: 150%;
}

/* INPUT FIELDS */
.input-box{
    position: relative;
    display: flex;
    flex-direction: column;
    margin: 20px 0;
}
.input-field{
    width: 100%;
    height: 55px;
    font-size: 16px;
    background: transparent;
    color: var(--black-color);
    padding: 0 20px;
    border: 1px solid var(--input-border-color);
    border-radius: 30px;
    outline: none;
    transition: var(--transition-3s);
}
.input-field:focus{
    border: 1px solid var(--primary-color);
}
.label{
    position: absolute;
    top: 50%;
    left: 20px;
    transform: translateY(-50%);
    color: var(--secondary-color);
    transition: 0.2s;
    cursor: text;
}
.input-field:focus ~ .label,
.input-field:valid ~ .label{
    top: 0;
    font-size: 14px;
    background-color: var(--white-color);
    color: var(--primary-color);
    padding: 0 10px;
}
.input-field:valid ~ .label{
    color: var(--secondary-color);
}
.icon{
    position: absolute;
    top: 50%;
    right: 25px;
    transform: translateY(-50%);
    font-size: 20px;
    color: var(--secondary-color);
}
/* FORGOT PASSWORD & TERMS AND CONDITIONS */
.form-cols{
    display: flex;
    justify-content: space-between;
    font-size: 14px;
}
.col-1{
    display: flex;
    align-items: center;
    gap: 6px;
}
/* SUBMIT BUTTON */
.btn-submit{
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    height: 50px;
    background-color: var(--primary-color);
    color: var(--white-color);
    font-size: 16px;
    font-weight: 500;
    border: none;
    border-radius: 30px;
    cursor: pointer;
    transition: var(--transition-3s);
}
.btn-submit:hover{
    gap: 15px;
}
.btn-submit i{
    font-size: 20px;
}
/* SWITCH FORM */
.switch-form{
    text-align: center;
}
.switch-form a{
    font-weight: 500;
}

/* RESPONSIVE STYLES */
@media only screen and (max-width: 564px){
    .wrapper{
        margin: 20px;
    }
}

JavaScript Interactivity

In the snippet above, you might have noticed functions like registerFunction() and loginFunction(). These functions (defined in your js/script.js file) handle the transition between the login and registration forms. A simple implementation could involve toggling the visibility of each form:

const loginForm = document.querySelector(".login-form");
const registerForm = document.querySelector(".register-form");
const wrapper = document.querySelector(".wrapper");
const loginTitle = document.querySelector(".title-login");
const registerTitle = document.querySelector(".title-register");
const signUpBtn = document.querySelector("#SignUpBtn");
const signInBtn = document.querySelector("#SignInBtn");

function loginFunction(){
    loginForm.style.left = "50%";
    loginForm.style.opacity = 1;
    registerForm.style.left = "150%";
    registerForm.style.opacity = 0;
    wrapper.style.height = "500px";
    loginTitle.style.top = "50%";
    loginTitle.style.opacity = 1;
    registerTitle.style.top = "50px";
    registerTitle.style.opacity = 0;
}

function registerFunction(){
    loginForm.style.left = "-50%";
    loginForm.style.opacity = 0;
    registerForm.style.left = "50%";
    registerForm.style.opacity = 1;
    wrapper.style.height = "580px";
    loginTitle.style.top = "-60px";
    loginTitle.style.opacity = 0;
    registerTitle.style.top = "50%";
    registerTitle.style.opacity = 1;
}

How to Build a Modern, Responsive Login & Registration Form with HTML, CSS, and JavaScript (Step-by-Step Guide)

Getting Started: The HTML Structure

Key Points in Our HTML:

Crafting the Login Form

Highlights:

Building the Register Form

Highlights:

Enhancing the Experience with CSS and JavaScript

CSS Styling

JavaScript Interactivity

Download source codes

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