In this tutorial, we will learn how to create a working chatbot using HTML, CSS, and JavaScript. In this chatbot, you can ask any question and receive instant responses. This chatbot is also responsive, which means you can use it on your phone too.

Timestamps:
0:00 Chatbot Demo
1:57 HTML & CSS Setup
16:14 JavaScript Initialization
17:29 Adding User Message to the Chatbox
21:00 Generating Response for User Messages
26:19 Auto-Scrolling the Chatbox
29:27 Toggling Chatbot Visibility with Button Click
33:23 Enabling Textarea Auto-Resize

Source Code:

HTML File

<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <title>Chatbot in JavaScript</title>
    <link rel="stylesheet" href="style.css">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- Google Fonts Link For Icons -->
    <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRAD@48,400,0,0" />
    <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Material+Symbols+Rounded:opsz,wght,FILL,GRAD@48,400,1,0" />
    <script src="script.js" defer></script>
  </head>
  <body>
    <button class="chatbot-toggler">
      <span class="material-symbols-rounded">mode_comment</span>
      <span class="material-symbols-outlined">close</span>
    </button>
    <div class="chatbot">
      <header>
        <h2>Chatbot</h2>
        <span class="close-btn material-symbols-outlined">close</span>
      </header>
      <ul class="chatbox">
        <li class="chat incoming">
          <span class="material-symbols-outlined">smart_toy</span>
          <p>Hi there 👋<br>How can I help you today?</p>
        </li>
      </ul>
      <div class="chat-input">
        <textarea placeholder="Enter a message..." spellcheck="false" required></textarea>
        <span id="send-btn" class="material-symbols-rounded">send</span>
      </div>
    </div>

  </body>
</html>

CSS File

/* Import Google font - Poppins */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600&display=swap');
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}
body {
  background: #E3F2FD;
}
.chatbot-toggler {
  position: fixed;
  bottom: 30px;
  right: 35px;
  outline: none;
  border: none;
  height: 50px;
  width: 50px;
  display: flex;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: #724ae8;
  transition: all 0.2s ease;
}
body.show-chatbot .chatbot-toggler {
  transform: rotate(90deg);
}
.chatbot-toggler span {
  color: #fff;
  position: absolute;
}
.chatbot-toggler span:last-child,
body.show-chatbot .chatbot-toggler span:first-child  {
  opacity: 0;
}
body.show-chatbot .chatbot-toggler span:last-child {
  opacity: 1;
}
.chatbot {
  position: fixed;
  right: 35px;
  bottom: 90px;
  width: 420px;
  background: #fff;
  border-radius: 15px;
  overflow: hidden;
  opacity: 0;
  pointer-events: none;
  transform: scale(0.5);
  transform-origin: bottom right;
  box-shadow: 0 0 128px 0 rgba(0,0,0,0.1),
              0 32px 64px -48px rgba(0,0,0,0.5);
  transition: all 0.1s ease;
}
body.show-chatbot .chatbot {
  opacity: 1;
  pointer-events: auto;
  transform: scale(1);
}
.chatbot header {
  padding: 16px 0;
  position: relative;
  text-align: center;
  color: #fff;
  background: #724ae8;
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.chatbot header span {
  position: absolute;
  right: 15px;
  top: 50%;
  display: none;
  cursor: pointer;
  transform: translateY(-50%);
}
header h2 {
  font-size: 1.4rem;
}
.chatbot .chatbox {
  overflow-y: auto;
  height: 510px;
  padding: 30px 20px 100px;
}
.chatbot :where(.chatbox, textarea)::-webkit-scrollbar {
  width: 6px;
}
.chatbot :where(.chatbox, textarea)::-webkit-scrollbar-track {
  background: #fff;
  border-radius: 25px;
}
.chatbot :where(.chatbox, textarea)::-webkit-scrollbar-thumb {
  background: #ccc;
  border-radius: 25px;
}
.chatbox .chat {
  display: flex;
  list-style: none;
}
.chatbox .outgoing {
  margin: 20px 0;
  justify-content: flex-end;
}
.chatbox .incoming span {
  width: 32px;
  height: 32px;
  color: #fff;
  cursor: default;
  text-align: center;
  line-height: 32px;
  align-self: flex-end;
  background: #724ae8;
  border-radius: 4px;
  margin: 0 10px 7px 0;
}
.chatbox .chat p {
  white-space: pre-wrap;
  padding: 12px 16px;
  border-radius: 10px 10px 0 10px;
  max-width: 75%;
  color: #fff;
  font-size: 0.95rem;
  background: #724ae8;
}
.chatbox .incoming p {
  border-radius: 10px 10px 10px 0;
}
.chatbox .chat p.error {
  color: #721c24;
  background: #f8d7da;
}
.chatbox .incoming p {
  color: #000;
  background: #f2f2f2;
}
.chatbot .chat-input {
  display: flex;
  gap: 5px;
  position: absolute;
  bottom: 0;
  width: 100%;
  background: #fff;
  padding: 3px 20px;
  border-top: 1px solid #ddd;
}
.chat-input textarea {
  height: 55px;
  width: 100%;
  border: none;
  outline: none;
  resize: none;
  max-height: 180px;
  padding: 15px 15px 15px 0;
  font-size: 0.95rem;
}
.chat-input span {
  align-self: flex-end;
  color: #724ae8;
  cursor: pointer;
  height: 55px;
  display: flex;
  align-items: center;
  visibility: hidden;
  font-size: 1.35rem;
}
.chat-input textarea:valid ~ span {
  visibility: visible;
}

@media (max-width: 490px) {
  .chatbot-toggler {
    right: 20px;
    bottom: 20px;
  }
  .chatbot {
    right: 0;
    bottom: 0;
    height: 100%;
    border-radius: 0;
    width: 100%;
  }
  .chatbot .chatbox {
    height: 90%;
    padding: 25px 15px 100px;
  }
  .chatbot .chat-input {
    padding: 5px 15px;
  }
  .chatbot header span {
    display: block;
  }
}

JavaScript File:

const chatbotToggler = document.querySelector(".chatbot-toggler");
const closeBtn = document.querySelector(".close-btn");
const chatbox = document.querySelector(".chatbox");
const chatInput = document.querySelector(".chat-input textarea");
const sendChatBtn = document.querySelector(".chat-input span");

let userMessage = null; // Variable to store user's message
const API_KEY = "PASTE-YOUR-API-KEY"; // Paste your API key here
const inputInitHeight = chatInput.scrollHeight;

const createChatLi = (message, className) => {
    // Create a chat <li> element with passed message and className
    const chatLi = document.createElement("li");
    chatLi.classList.add("chat", `${className}`);
    let chatContent = className === "outgoing" ? `<p></p>` : `<span class="material-symbols-outlined">smart_toy</span><p></p>`;
    chatLi.innerHTML = chatContent;
    chatLi.querySelector("p").textContent = message;
    return chatLi; // return chat <li> element
}

const generateResponse = (chatElement) => {
    const API_URL = "https://api.openai.com/v1/chat/completions";
    const messageElement = chatElement.querySelector("p");

    // Define the properties and message for the API request
    const requestOptions = {
        method: "POST",
        headers: {
            "Content-Type": "application/json",
            "Authorization": `Bearer ${API_KEY}`
        },
        body: JSON.stringify({
            model: "gpt-3.5-turbo",
            messages: [{role: "user", content: userMessage}],
        })
    }

    // Send POST request to API, get response and set the reponse as paragraph text
    fetch(API_URL, requestOptions).then(res => res.json()).then(data => {
        messageElement.textContent = data.choices[0].message.content.trim();
    }).catch(() => {
        messageElement.classList.add("error");
        messageElement.textContent = "Oops! Something went wrong. Please try again.";
    }).finally(() => chatbox.scrollTo(0, chatbox.scrollHeight));
}

const handleChat = () => {
    userMessage = chatInput.value.trim(); // Get user entered message and remove extra whitespace
    if(!userMessage) return;

    // Clear the input textarea and set its height to default
    chatInput.value = "";
    chatInput.style.height = `${inputInitHeight}px`;

    // Append the user's message to the chatbox
    chatbox.appendChild(createChatLi(userMessage, "outgoing"));
    chatbox.scrollTo(0, chatbox.scrollHeight);
    
    setTimeout(() => {
        // Display "Thinking..." message while waiting for the response
        const incomingChatLi = createChatLi("Thinking...", "incoming");
        chatbox.appendChild(incomingChatLi);
        chatbox.scrollTo(0, chatbox.scrollHeight);
        generateResponse(incomingChatLi);
    }, 600);
}

chatInput.addEventListener("input", () => {
    // Adjust the height of the input textarea based on its content
    chatInput.style.height = `${inputInitHeight}px`;
    chatInput.style.height = `${chatInput.scrollHeight}px`;
});

chatInput.addEventListener("keydown", (e) => {
    // If Enter key is pressed without Shift key and the window 
    // width is greater than 800px, handle the chat
    if(e.key === "Enter" && !e.shiftKey && window.innerWidth > 800) {
        e.preventDefault();
        handleChat();
    }
});

sendChatBtn.addEventListener("click", handleChat);
closeBtn.addEventListener("click", () => document.body.classList.remove("show-chatbot"));
chatbotToggler.addEventListener("click", () => document.body.classList.toggle("show-chatbot"));

Please note that your chatbot is currently unable to retrieve responses to your questions because you have not provided your API key in the AP_KEY variable. To get a free API key from OpenAI, sign up for an account at https://platform.openai.com/account/api-keys.

Happy Coding !!!

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How to Create a Working Chatbot using HTML, CSS, and JavaScript
26.50 GEEK