To add a dropdown button follow this Link

Add following code to style:

<style>
.container {
 overflow: hidden;
 background-color: #333;
 font-family: Arial;
}

.container a {
 float: left;
 font-size: 16px;
 color: white;
 text-align: center;
 padding: 14px 16px;
 text-decoration: none;
}

.dropdown {
 float: left;
 overflow: hidden;
}

.dropdown .dropbtn {
 cursor: pointer;
 font-size: 16px; 
 border: none;
 outline: none;
 color: white;
 padding: 14px 16px;
 background-color: inherit;
}

.container a:hover, .dropdown:hover .dropbtn {
 background-color: red;
}

.dropdown-content {
 display: none;
 position: absolute;
 background-color: #f9f9f9;
 min-width: 160px;
 box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
 z-index: 1;
}

.dropdown-content a {
 float: none;
 color: black;
 padding: 12px 16px;
 text-decoration: none;
 display: block;
 text-align: left;
}

.dropdown-content a:hover {
 background-color: #ddd;
}

.show {
 display: block;
}
</style>

Then add following code to make sure your animation works:

<li id="Animations">
	<a href="#">Animations</a>
	<ul class="subnav">
		<li><a <button id="rotate-left" title="Rotate clockwise">clockwise</button></a></li>
		<li><a <button id="rotate-right" title="Rotate counterclockwise">anticlockwise</button></a></li>
		<li> <a <button id="pan-to-main_gate">Main Gate</button></a> </li>
		<li><a <button id="pan-to-boyshostel">Boys Hostel</button></a></li>
		<li><a <button id="elastic-to-auditorium">Auditorium</button></a></li>
		<li><a <button id="bounce-to-workshop">Workshop</button></a></li>
		<li><a <button id="spin-to-mba_block">MBA Block</button></a></li>
		<li><a <button id="fly-to-pg_block">PG Block</button></a></li>
		<li><a <button id="pan-to-library">Library</button></a></li>
		<li><a <button id="pan-to-sports">Sports</button></a></li>
		</ul>
	</li>
</ul>

Problems Faced:

Dropdown button was overlapped by Map’s layer and dropdown button was not working.

Solution:

My friend Amritpal Singh suggested to add following code in style and It worked.

<style>
.ol-viewport{
	z-index:-1;
}

Output: