If you want to create your own shopping cart in HTM5, CSS3, and JS, you are in the right place! This is how to create a shopping cart. This also includes Payment integration from the Payment Request API!

1. Create the files

Create a folder and put these files in it:

index.html
style.css
script.js

2. Add HTML

Put this in index.html:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Shopping Cart</title>
    <link rel="stylesheet" href="styles.css">
</head>
<body>
    <div class="products">
        <div class="product">
            <h2>Product 1</h2>
            <p>$10</p>
            <button onclick="addToCart('Product 1', 10)">Add to Cart</button>
        </div>
        <!-- Add more products as needed -->
    </div>
    <div class="cart">
        <h2>Shopping Cart</h2>
        <ul id="cart-items"></ul>
        <p>Total: $<span id="cart-total">0</span></p>
    </div>
    <script src="script.js"></script>
</body>
</html>

3. Add CSS

Put this in style.css:

.products, .cart {
    margin: 20px;
}
.product, .cart-item {
    margin-bottom: 10px;
}

4. Add Javascript

Put this in script.js:

let cart = [];

function addToCart(name, price) {
    const item = cart.find(product => product.name === name);
    if (item) {
        item.quantity++;
    } else {
        cart.push({ name, price, quantity: 1 });
    }
    updateCart();
}

function removeFromCart(name) {
    cart = cart.filter(product => product.name !== name);
    updateCart();
}

function updateCart() {
    const cartItems = document.getElementById('cart-items');
    const cartTotal = document.getElementById('cart-total');
    cartItems.innerHTML = '';
    let total = 0;
    cart.forEach(product => {
        const li = document.createElement('li');
        li.textContent = `${product.name} - $${product.price} x ${product.quantity}`;
        const removeButton = document.createElement('button');
        removeButton.textContent = 'Remove';
        removeButton.onclick = () => removeFromCart(product.name);
        li.appendChild(removeButton);
        cartItems.appendChild(li);
        total += product.price * product.quantity;
    });
    cartTotal.textContent = total;
}
const paymentRequest = new PaymentRequest(
  [
    {
      supportedMethods: 'basic-card',
      data: {
        supportedNetworks: ['visa', 'mastercard'],
      },
    },
  ],
  {
    total: {
      label: 'Total',
      amount: { currency: 'USD', value: '10.00' },
    },
  }
);
paymentRequest.show().then((paymentResponse) => {
  // Process the payment
  console.log(paymentResponse);

  // Complete the payment
  paymentResponse.complete('success').then(() => {
    console.log('Payment completed successfully');
  });
}).catch((error) => {
  console.error('Payment failed', error);
});

5. Explaining the JS file

1. Shopping cart functionality

Initialize the cart

let cart = [];

cart: An empty array to store items added to the cart.

2 Add items to the cart

function addToCart(name, price) {
    const item = cart.find(product => product.name === name);
    if (item) {
        item.quantity++;
    } else {
        cart.push({ name, price, quantity: 1 });
    }
    updateCart();
}

addToCart(name, price): Function to add items to the cart.
cart.find(product => product.name === name): Searches for an item in the cart by name.
if(item): If an item is found, it increments the quantity.
else: If the item is not found, it adds a new item to the cart with the specified name, price, and a quantity of 1.
updateCart(): Calls the updateCart function to refresh the cart display.

3 Remove items from the cart

function removeFromCart(name) {
    cart = cart.filter(product => product.name !== name);
    updateCart();
}

removeFromCart(name): Function to remove items from the cart.
cart.filter(product => product.name !== name): Filters out the item with the specified name from the cart.
updateCart(): Calls the updateCart function to refresh the cart display.

4 Update the cart display

function updateCart() {
    const cartItems = document.getElementById('cart-items');
    const cartTotal = document.getElementById('cart-total');
    cartItems.innerHTML = '';
    let total = 0;
    cart.forEach(product => {
        const li = document.createElement('li');
        li.textContent = `${product.name} - $${product.price} x ${product.quantity}`;
        const removeButton = document.createElement('button');
        removeButton.textContent = 'Remove';
        removeButton.onclick = () => removeFromCart(product.name);
        li.appendChild(removeButton);
        cartItems.appendChild(li);
        total += product.price * product.quantity;
    });
    cartTotal.textContent = total;
}

updateCart(): Function that updates the cart display.
cartItems: Gets the HTML element with the ID cart-items.
cartTotal: Gets the HTML element with the ID cart-total.
cartItems.innerHTML = '': Clears the current cart items display.
let total = 0: Initializes the total amount to 0.
cart.forEach(product => { ... }): Iterates over each product in the cart.
document.createElement('li'): Creates a new list item element.
li.textContent = ${product.name} - $${product.price} x ${product.quantity}: Sets the text content of the list item.
document.createElement(‘button’): Creates a new button element.
removeButton.textContent = 'Remove': Sets the text content of the button.
removeButton.onclick = () => removeFromCart(product.name): Sets the button’s click event to call removeFromCart.
li.appendChild(removeButton): Adds the button to the list item.
cartItems.appendChild(li): Adds the list item to the cart items display.
total += product.price * product.quantity: Adds the product's total price to the total amount.
cartTotal.textContent = total: Updates the total amount display.

Payment Request API

Create a Payment Request object

const paymentRequest = new PaymentRequest(
  [
    {
      supportedMethods: 'basic-card',
      data: {
        supportedNetworks: ['visa', 'mastercard'],
      },
    },
  ],
  {
    total: {
      label: 'Total',
      amount: { currency: 'USD', value: '10.00' },
    },
  }
);

PaymentRequest: Creates a new payment request.
supportedMethods: Specifies the payment methods supported (e.g., ‘basic-card’).
data: Contains additional information about the payment method, such as supported networks.
total: Represents the total amount to be charged.

2 Show the Payment Request

paymentRequest.show().then((paymentResponse) => {
  // Process the payment
  console.log(paymentResponse);

  // Complete the payment
  paymentResponse.complete('success').then(() => {
    console.log('Payment completed successfully');
  });
}).catch((error) => {
  console.error('Payment failed', error);
});

show(): Displays the payment interface to the user.
then((paymentResponse) => { ... }): If the user approves the payment, this promise resolves with a paymentResponse object.
paymentResponse: Contains the user’s payment details.
console.log(paymentResponse): Logs the payment response for processing.
catch((error) => { ... }): If the payment fails or is canceled, this promise catches the error and logs it.

Summary

This code manages a shopping cart by adding, removing, and updating items, and then processes a payment using the Payment Request API. If you have any more questions or need further clarification, feel free to ask in the comments!

Conclusion

That concludes my article about creating a shopping cart with payment integration in HTML5, CSS3, and JS! Make sure to leave a comment and a reaction and check out more of my stuff!

How to create a simple shopping cart in HTML5, CSS3, and JS with Payment integration