<div class="container">
      <div class="row">
        <div class="col-md-5">
            <div class="panel panel-primary">
                <div class="panel-heading">
                    <span class="glyphicon glyphicon-comment"></span> Chat
                    <div class="btn-group pull-right">
                        <button type="button" class="btn btn-default btn-xs dropdown-toggle" data-toggle="dropdown">
              <span class="glyphicon glyphicon-chevron-down"></span>
            </button>
                       <ul class="dropdown-menu slidedown">
                            <li><a href="#"><span class="glyphicon glyphicon-refresh"></span>Refresh</a></li>
                            <li><a href="#"><span class="glyphicon glyphicon-ok-sign"></span>Available</a></li>
                            <li><a href="#"><span class="glyphicon glyphicon-remove"></span>Busy</a></li>
                            <li><a href="#"><span class="glyphicon glyphicon-time"></span>Away</a></li>
                            <li class="divider"></li>
                            <li><a href="#"><span class="glyphicon glyphicon-off"></span>Sign Out</a></li>
                        </ul>
                    </div>
                </div>
                <div class="panel-body">
                    <ul class="chat">
                        <li class="left clearfix">
                            <span class="chat-img pull-left">
              <img src="http://placehold.it/50/55C1E7/fff&text=JS" alt="User Avatar" class="img-circle" />
            </span>
                            <div class="chat-body clearfix">
                                <div class="header">
                                    <strong class="primary-font">Jack Sparrow</strong> <small class="pull-right text-muted">
                <span class="glyphicon glyphicon-time"></span>12 mins ago</small>
                                </div>
                                <p>
                                    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur bibendum ornare dolor, quis ullamcorper ligula sodales.
                                </p>
                            </div>
                        </li>
                        <li class="right clearfix"><span class="chat-img pull-right">
                            <img src="http://placehold.it/50/FA6F57/fff&text=BP" alt="User Avatar" class="img-circle" />
                        </span>
                            <div class="chat-body clearfix">
                                <div class="header">
                                    <small class=" text-muted"><span class="glyphicon glyphicon-time"></span>13 mins ago</small>
                                    <strong class="pull-right primary-font">Bhaumik Patel</strong>
                                </div>
                                <p>
                                    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur bibendum ornare dolor, quis ullamcorper ligula sodales.
                                </p>
                            </div>
                        </li>
                        <li class="left clearfix"><span class="chat-img pull-left">
                            <img src="http://placehold.it/50/55C1E7/fff&text=JS" alt="User Avatar" class="img-circle" />
                        </span>
                            <div class="chat-body clearfix">
                                <div class="header">
                                    <strong class="primary-font">Jack Sparrow</strong> <small class="pull-right text-muted">
                                        <span class="glyphicon glyphicon-time"></span>14 mins ago</small>
                                </div>
                                <p>
                                    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur bibendum ornare dolor, quis ullamcorper ligula sodales.
                                </p>
                            </div>
                        </li>
                        <li class="right clearfix"><span class="chat-img pull-right">
                            <img src="http://placehold.it/50/FA6F57/fff&text=BP" alt="User Avatar" class="img-circle" />
                        </span>
                            <div class="chat-body clearfix">
                                <div class="header">
                                    <small class=" text-muted"><span class="glyphicon glyphicon-time"></span>15 mins ago</small>
                                    <strong class="pull-right primary-font">Bhaumik Patel</strong>
                                </div>
                                <p>
                                    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur bibendum ornare dolor, quis ullamcorper ligula sodales.
                                </p>
                            </div>
                        </li>
                    </ul>
                </div>
                <div class="panel-footer">
                    <div class="input-group">
                        <input id="btn-input" type="text" class="form-control input-sm" placeholder="Type your message here..." />
                        <span class="input-group-btn">
                            <button class="btn btn-warning btn-sm" id="btn-chat">
                                Send</button>
                        </span>
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>
.chat
{
    list-style: none;
    margin: 0;
    padding: 0;
}

.chat li
{
    margin-bottom: 10px;
    padding-bottom: 5px;
    border-bottom: 1px dotted #B3A9A9;
}

.chat li.left .chat-body
{
    margin-left: 60px;
}

.chat li.right .chat-body
{
    margin-right: 60px;
}


.chat li .chat-body p
{
    margin: 0;
    color: #777777;
}

.panel .slidedown .glyphicon, .chat .glyphicon
{
    margin-right: 5px;
}

.panel-body
{
    overflow-y: scroll;
    height: 250px;
}

::-webkit-scrollbar-track
{
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,0.3);
    background-color: #F5F5F5;
}

::-webkit-scrollbar
{
    width: 12px;
    background-color: #F5F5F5;
}

::-webkit-scrollbar-thumb
{
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,.3);
    background-color: #555;
}

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js
  2. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js