<div class="chat-box">
  <header>
    <h1>André F. Martins</h1>
    <span style="flex:1"></span>
    <span class="close-button">X</span>
  </header>
  <section id="message-list">
  </section>
  <footer>
    <input id="message-input" type="text" placeholder="Type a message...">
  </footer>
</div>
@import url('https://fonts.googleapis.com/css?family=Karla')

*
  box-sizing: border-box

::selection
  background: #fd0
  color: #222

br
  font-size: 0

body
  font-family: "Karla", sans-serif
  margin: 0
  display: flex
  align-items: center
  justify-content: center
  width: 100vw
  height: 100vh
  font-size: 16px
  background-color: #ddd

.chat-box
  width: 300px
  height: 400px
  background-color: #eee
  border-radius: 16px 16px 0 0
  overflow: hidden
  border: 2px #45f solid
  
  header
    background-color: #45f
    color: #fff
    display: flex
    padding: 0 16px
    
    > *  
      line-height: 40px

    h1
      margin: 0
      font-size: 1.1em
      
    .close-button
      cursor: pointer
      user-select: none
  
  section
    overflow-y: scroll
    overflow-x: hidden
    height: calc(100% - 40px - 40px)
    padding: 12px
    
    div
      margin: 12px 0

    span
      display: inline-block
      padding: 6px 8px
      margin: 1px 0
      max-width: 90%
      word-wrap: break-word
      
    div.me
      text-align: left
      span      
        background-color: #68c
        border-radius: 4px 16px 16px 4px
      span:first-of-type
        border-top-left-radius: 16px
      span:last-of-type
        border-bottom-left-radius: 16px
        
        
    div.not-me
      text-align: right
      span      
        background-color: #bcf
        border-radius: 16px 4px 4px 16px
      span:first-of-type
        border-top-right-radius: 16px
      span:last-of-type
        border-bottom-right-radius: 16px
  
  footer
    input
      font-family: "Karla", sans-serif
      outline: 0
      padding: 0 12px
      height: 40px
      width: 100%
      font-size: 1em
View Compiled
function sendMessage(message, itsMe) { // ...Mario
  var messageList = document.getElementById("message-list");
  
  var scrollToBottom = (messageList.scrollHeight - messageList.scrollTop - messageList.clientHeight < 80);

  var lastMessage = messageList.children[messageList.children.length-1];
  
  var newMessage = document.createElement("span");
  newMessage.innerHTML = message;

  var className;
  
  if(itsMe)
  {
    className = "me";
    scrollToBottom = true;
  }
  else
  {
    className = "not-me";
  }
  
  if(lastMessage && lastMessage.classList.contains(className))
  {
    lastMessage.appendChild(document.createElement("br"));
    lastMessage.appendChild(newMessage);
  }
  else
  {
    var messageBlock = document.createElement("div");
    messageBlock.classList.add(className);
    messageBlock.appendChild(newMessage);
    messageList.appendChild(messageBlock);
  }
  
  if(scrollToBottom)
    messageList.scrollTop = messageList.scrollHeight;
}

var message = document.getElementById("message-input");
message.addEventListener("keypress", function(event) {
  var key = event.which || event.keyCode;
  if(key === 13 && this.value.trim() !== "")
  {
    sendMessage(this.value, true);
    this.value = "";
  }
});

sendMessage("Hello!", true);
sendMessage("Hey!", false);
sendMessage("How are you doing?", false);
sendMessage("I'm doing well.", true);
sendMessage("What about you?", true);
sendMessage("Good", false);

function sendRandomMessages()
{
  // http://www.conversationstarters.com/generator.php
  var messageList = [
    "What is your biggest concern about the future?",
    "What is your biggest fear?",
    "At what age would you consider someone to be old?",
    "What is your favorite home cooked dish?",
    "What is the biggest priority in your life right now?",
    "Where did you go on your last vacation?",
    "What was the biggest life change you've gone through?",
    "Do you have any siblings?",
    "What's your family like?",
    "If you knew that you only had a year left to live, what would you do?",
    "What do you usually eat in the morning?",
    "What's in your fridge?",
    "Do you recycle?",
    "What are some things that you should not not say during a job interview?",
    "If you could go back in time and change one thing, what would that be?",
    "What do you wear to sleep?",
    "What is the last thing you do before you go to sleep?",
    "If you could only eat one thing for the rest of your life, what would it be?",
    "Would you rather be homeless for a year or be in jail for a year?",
    "What do you do for fun?"
  ];
  var choosenMessage = messageList[Math.floor(Math.random() * messageList.length)];
  
  sendMessage(choosenMessage, false);
  
  setTimeout(sendRandomMessages, Math.random()*10000 + 7000);
}

sendRandomMessages();

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.